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  • Boiler plate code replacement - is there anything bad about this code?

    - by Benjol
    I've recently created these two (unrelated) methods to replace lots of boiler-plate code in my winforms application. As far as I can tell, they work ok, but I need some reassurance/advice on whether there are some problems I might be missing. (from memory) static class SafeInvoker { //Utility to avoid boiler-plate InvokeRequired code //Usage: SafeInvoker.Invoke(myCtrl, () => myCtrl.Enabled = false); public static void Invoke(Control ctrl, Action cmd) { if (ctrl.InvokeRequired) ctrl.BeginInvoke(new MethodInvoker(cmd)); else cmd(); } //Replaces OnMyEventRaised boiler-plate code //Usage: SafeInvoker.RaiseEvent(this, MyEventRaised) public static void RaiseEvent(object sender, EventHandler evnt) { var handler = evnt; if (handler != null) handler(sender, EventArgs.Empty); } } EDIT: See related question here UPDATE Following on from deadlock problems (related in this question), I have switched from Invoke to BeginInvoke (see an explanation here). Another Update Regarding the second snippet, I am increasingly inclined to use the 'empty delegate' pattern, which fixes this problem 'at source' by declaring the event directly with an empty handler, like so: event EventHandler MyEventRaised = delegate {};

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  • DbDataReader with DbTransactions

    - by Gustavo Paulillo
    Its the wrong way or lack of performance, using DbDataReader combinated with DbTransactions? An example of code: public DbDataReader ExecuteReader() { try { if (this._baseConnection.State == ConnectionState.Closed) this._baseConnection.Open(); if (this._baseCommand.Transaction != null) return this._baseCommand.ExecuteReader(); return this._baseCommand.ExecuteReader(CommandBehavior.CloseConnection); } catch (Exception excp) { if (this._baseCommand.Transaction != null) this._baseCommand.Transaction.Rollback(); this._baseCommand.CommandText = string.Empty; this._baseConnection.Close(); throw new Exception(excp.Message); } } Some methods call this operation. Sometimes openning a DbTransaction. Its using DbConnection and DbCommand. The real problem, is in production enviroment (like 5,000 access/day) the ADO operations start throwing exceptions

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  • Is there an easy way to get a list of all successful captures from a regex pre-5.10?

    - by Chas. Owens
    I know the right way to do this if I have Perl 5.10 is to use named captures and values %+, but in Perl 5.8.9 and how can I get a list of successful captures? I have come up with two methods that are both just terrible: #you need to list each possible match my @captures = grep { defined } ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15, $16); and #ew, I turned on symbolic references { no strict 'refs'; my @captures = map { defined $+[$_] ? $$_ : () } 1 .. $#+; } There is a third option I have found involving (?{}), but it requires global variables (because the closure happens at compile time) and takes the regex from reasonably clear to ungodly mess. The only alternative I have found is to capture the whole match and then use another set of regexes to get the values I want (actually I build the first regex out of the other regexes because there is no good reason to duplicate the logic).

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  • Problems with :uniq => true/Distinct option in a has_many_through association w/ named scope (Rails)

    - by MikeH
    I had to make some tweaks to my app to add new functionality, and my changes seem to have broken the :uniq option that was previously working perfectly. Here's the set up: #User.rb has_many :products, :through = :seasons, :uniq = true has_many :varieties, :through = :seasons, :uniq = true #product.rb has_many :seasons has_many :users, :through = :seasons, :uniq = true has_many :varieties #season.rb belongs_to :product belongs_to :variety belongs_to :user named_scope :by_product_name, :joins = :product, :order = 'products.name' #variety.rb belongs_to :product has_many :seasons has_many :users, :through = :seasons, :uniq = true First I want to show you the previous version of the view that is now breaking, so that we have a baseline to compare. The view below is pulling up products and varieties that belong to the user. In both versions below, I've assigned the same products/varieties to the user so the logs will looking at the exact same use case. #user/show <% @user.products.each do |product| %> <%= link_to product.name, product %> <% @user.varieties.find_all_by_product_id(product.id).each do |variety| %> <%=h variety.name.capitalize %></p> <% end %> <% end %> This works. It displays only one of each product, and then displays each product's varieties. In the log below, product ID 1 has 3 associated varieties. And product ID 43 has none. Here's the log output for the code above: Product Load (11.3ms) SELECT DISTINCT `products`.* FROM `products` INNER JOIN `seasons` ON `products`.id = `seasons`.product_id WHERE ((`seasons`.user_id = 1)) ORDER BY name, products.name Product Columns (1.8ms) SHOW FIELDS FROM `products` Variety Columns (1.9ms) SHOW FIELDS FROM `varieties` Variety Load (0.7ms) SELECT DISTINCT `varieties`.* FROM `varieties` INNER JOIN `seasons` ON `varieties`.id = `seasons`.variety_id WHERE (`varieties`.`product_id` = 1) AND ((`seasons`.user_id = 1)) ORDER BY name Variety Load (0.5ms) SELECT DISTINCT `varieties`.* FROM `varieties` INNER JOIN `seasons` ON `varieties`.id = `seasons`.variety_id WHERE (`varieties`.`product_id` = 43) AND ((`seasons`.user_id = 1)) ORDER BY name Ok, so everything above is the previous version which was working great. In the new version, I added some columns to the join table called seasons, and made a bunch of custom methods that query those columns. As a result, I made the following changes to the view code that you saw above so that I could access those methods on the seasons model: <% @user.seasons.by_product_name.each do |season| %> <%= link_to season.product.name, season.product %> #Note: I couldn't get this loop to work at all, so I settled for the following: #<% @user.varieties.find_all_by_product_id(product.id).each do |variety| %> <%=h season.variety.name.capitalize %> <%end%> <%end%> Here's the log output for that: SQL (0.9ms) SELECT count(DISTINCT "products".id) AS count_products_id FROM "products" INNER JOIN "seasons" ON "products".id = "seasons".product_id WHERE (("seasons".user_id = 1)) Season Load (1.8ms) SELECT "seasons".* FROM "seasons" INNER JOIN "products" ON "products".id = "seasons".product_id WHERE ("seasons".user_id = 1) AND ("seasons".user_id = 1) ORDER BY products.name Product Load (0.7ms) SELECT * FROM "products" WHERE ("products"."id" = 43) ORDER BY products.name CACHE (0.0ms) SELECT "seasons".* FROM "seasons" INNER JOIN "products" ON "products".id = "seasons".product_id WHERE ("seasons".user_id = 1) AND ("seasons".user_id = 1) ORDER BY products.name Product Load (0.4ms) SELECT * FROM "products" WHERE ("products"."id" = 1) ORDER BY products.name Variety Load (0.4ms) SELECT * FROM "varieties" WHERE ("varieties"."id" = 2) ORDER BY name CACHE (0.0ms) SELECT * FROM "products" WHERE ("products"."id" = 1) ORDER BY products.name Variety Load (0.4ms) SELECT * FROM "varieties" WHERE ("varieties"."id" = 8) ORDER BY name CACHE (0.0ms) SELECT * FROM "products" WHERE ("products"."id" = 1) ORDER BY products.name Variety Load (0.4ms) SELECT * FROM "varieties" WHERE ("varieties"."id" = 7) ORDER BY name CACHE (0.0ms) SELECT * FROM "products" WHERE ("products"."id" = 43) ORDER BY products.name CACHE (0.0ms) SELECT count(DISTINCT "products".id) AS count_products_id FROM "products" INNER JOIN "seasons" ON "products".id = "seasons".product_id WHERE (("seasons".user_id = 1)) CACHE (0.0ms) SELECT "seasons".* FROM "seasons" INNER JOIN "products" ON "products".id = "seasons".product_id WHERE ("seasons".user_id = 1) AND ("seasons".user_id = 1) ORDER BY products.name CACHE (0.0ms) SELECT * FROM "products" WHERE ("products"."id" = 1) ORDER BY products.name CACHE (0.0ms) SELECT * FROM "products" WHERE ("products"."id" = 1) ORDER BY products.name CACHE (0.0ms) SELECT * FROM "varieties" WHERE ("varieties"."id" = 8) ORDER BY name I'm having two problems: (1) The :uniq option is not working for products. Three distinct versions of the same product are displaying on the page. (2) The :uniq option is not working for varieties. I don't have validation set up on this yet, and if the user enters the same variety twice, it does appear on the page. In the previous working version, this was not the case. The result I need is that only one product for any given ID displays, and all varieties associated with that ID display along with such unique product. One thing that sticks out to me is the sql call in the most recent log output. It's adding 'count' to the distinct call. I'm not sure why it's doing that or whether it might be an indication of an issue. I found this unresolved lighthouse ticket that seems like it could potentially be related, but I'm not sure if it's the same issue: https://rails.lighthouseapp.com/projects/8994/tickets/2189-count-breaks-sqlite-has_many-through-association-collection-with-named-scope I've tried a million variations on this and can't get it working. Any help is much appreciated!

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  • How do I Resolve dependancies that rely on transient context data using castle windsor?

    - by Dan Ryan
    I have a WCF service application that uses a component called EnvironmentConfiguration that holds configuration information for my application. I am converting this service so that it can be used by different applications that have different configuration requirements. I want to identify the configuration to use by allowing an additional parameter to be passed to the service call i.e. public void DoSomething(string originalParameter, string callingApplication) What is the recommended way to alter the behaviour of the EnvironmentConfiguration class based on the transient data (callingApplication) without having to pass the callingApplication variable to all the component methods that need configuration information?

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  • distance between two points across land using sql server

    - by dpwb
    I am looking to calculate the shortest distance between two points inside SQL Server 2008 taking into account land mass only. I have used the geography data type along with STDistance() to work out point x distance to point y as the crow flies, however this sometimes crosses the sea which i am trying to avoid. I have also created a polygon around the land mass boundary I am interested in. I believe that I need to combine these two methods to ensure that STDistance always remains within polygon - unless there is a simpler solution. Thanks for any advice

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  • Converting app to MVC and running it in both console and gui

    - by terence6
    I have a simple java gui calculator, with 3 number systems (there are some bugs but that doesn't matter now). Currently all code is in one file. My task is to rewrite it as MVC, and add possibility to run it in either gui or console mode. How should I divide this program to organise it as M-V-C ? Is it written properly enough to add console functionality to it? (guess I'll have to change all methods invoking to JLabel Output to something simply storing an output String as a model argument and then having View to get it). Here's the starting code : http://paste.pocoo.org/show/224566/ Here's what I already have : Main : http://paste.pocoo.org/show/224567/ Model : http://paste.pocoo.org/show/224570/ View : http://paste.pocoo.org/show/224569/ Controller : http://paste.pocoo.org/show/224568/ I don't have view in my model so I can't call to Output. That's the first problem I can see.

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  • Dictionary with delegate or switch?

    - by Samvel Siradeghyan
    Hi, I am writing a parser, which call some functions dependent on some value. I can implement this logic with simple switch like this switch(some_val) { case 0: func0(); break; case 1: func1(); break; } or with delegates and dictionary like this delegate void some_delegate(); Dictionary<int, some_delegate> some_dictionary = new Dictionary<int, some_delegate>(); some_dictionary[0] = func0; some_dictionary[1] = func1; some_dictionary[some_value].Invoke(); Are this two methods equal and which is preferred? Thanks.

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  • fastest (low latency) method for Inter Process Communication between Java and C/C++

    - by Bastien
    Hello, I have a Java app, connecting through TCP socket to a "server" developed in C/C++. both app & server are running on the same machine, a Solaris box (but we're considering migrating to Linux eventually). type of data exchanged is simple messages (login, login ACK, then client asks for something, server replies). each message is around 300 bytes long. Currently we're using Sockets, and all is OK, however I'm looking for a faster way to exchange data (lower latency), using IPC methods. I've been researching the net and came up with references to the following technologies: - shared memory - pipes - queues but I couldn't find proper analysis of their respective performances, neither how to implement them in both JAVA and C/C++ (so that they can talk to each other), except maybe pipes that I could imagine how to do. can anyone comment about performances & feasibility of each method in this context ? any pointer / link to useful implementation information ? thanks for your help

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  • C# Operator Overloading post-fix increment

    - by Victor
    I'm coding a date class and am having trouble with the post-fix increment (the prefix increment seems fine). Here is the sample code: public class date { int year, month, day; public date(int d, int m, int y) { day = d; month = m; year = y; } static public date operator ++(date d) { return d.Next(d); } } The method "Next(date d)" takes a date and returns tomorrows date (I left it out for brevity). I'm to young in C# to understand why the prefix is fine but postfix increment does nothing. But remember in C++ we would have to have two methods instead of just one - for prefix and postfix increments. Also no errors or warnings on compile.

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  • Why is IHttpAsyncHandler being called over IHttpHandler?

    - by Tim Hardy
    I made a custom handler that derives from MvcHandler. I have my routes using a custom RouteHandler that returns my new handler for GetHttpHandler(), and I override ProcessRequest() in my custom handler. The call to GetHttpHandler is triggering a breakpoint and my handler's constructor is definitely being called, but BeginProcessRequest() is being called on the base MvcHandler instead of ProcessRequest(). Why are the async methods being called when I haven't done anything to call them? I don't want asynchronous handling, and I certainly didn't do anything explicit to get it. My controllers all derive from Controller, not AsyncController. I don't have the source code with me right now, but I can add it later if needed. I was hoping someone might know some of the reasons why BeginProcessRequest might be called when it's not wanted.

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  • UITableView's cellForRowAtIndexPath is not getting called after low memory warning

    - by Jinesh
    I am new to COCOA and Objective C. I am working on an application which have two controllers with one table view in each, clicking an item form this table will lead to another controller to be pushed to the stack. All was working fine till i started handling low memory warning in app delegate. What i am doing in app delegate's applicationDidReceiveMemoryWarning is, deleting all of my model and popping out all controllers to its root view using popToRootViewControllerAnimated. Now my problem starts, once low mem warning is received table's cellForRowAtIndexPath is not getting called. All other methods of UITableViewDataSource is properly called. What i get on screen is a blank white screen. I am testing my app in iPhone OS 3.0 and development is done in Xcode V 3.1.3. Hope you guys can help me to nail this. Thanks in advance, Jinesh.

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  • Database Design Primay Key, ID vs String

    - by LnDCobra
    Hi, I am currently planning to develop a music streaming application. And i am wondering what would be better as a primary key in my tables on the server. An ID int or a Unique String. Methods 1: Songs Table: SongID(int), Title(string), Artist*(string), Length(int), Album*(string) Genre Table Genre(string), Name(string) SongGenre: SongID*(int), Genre*(string) Method 2 Songs Table: SongID(int), Title(string), ArtistID*(int), Length(int), AlbumID*(int) Genre Table GenreID(int), Name(string) SongGenre: SongID*(int), GenreID*(int) Key: Bold = Primary Key, Field* = Foreign Key I'm currently designing using method 2 as I believe it will speed up lookup performance and use less space as an int takes a lot less space then a string. Is there any reason this isn't a good idea? Is there anything I should be aware of?

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  • calling Overloaded method from a generic method.

    - by asela38
    How to create a generic method which can call overloaded methods? I tried but it gives a compilation error. Test.java:19: incompatible types found : java.lang.Object required: T T newt = getCloneOf(t); ^ import java.util.*; public class Test { private Object getCloneOf(Object s) { return new Object(); } private String getCloneOf(String s) { return new String(s); } private <T> Set<T> getCloneOf(Set<T> set){ Set<T> newSet = null; if( null != set) { newSet = new HashSet<T>(); for (T t : set) { T newt = getCloneOf(t); newSet.add(newt); } } } }

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  • How write an ads server

    - by Nisanio
    Hi everyone I want to write an ads server (like OpenX), just for fun and learning (they aren't the same). But my idea, more than writing an entire application with web interface and so on, is to write a very tiny core that provides the basic functionality in the most efficient way, like a library that other people can use to write a complete application more fitted to their needs. The objective is to make it small, very efficient and fast. Can someone help me with a list of the minimal functionality needed for this kind of application?. An Ads Server isn't only a banner delivery, there are differents methods (for example OpenX uses a very weird javascript code that i don't understand completely) Any help or guidance is more than welcome...Thanks

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  • Handling changes in an interface shared across multiple solutions?

    - by Anthony Mastrean
    Our "main" solution is the development code: shared libraries, services, UI projects, etc. The other solution is an integration and automated tests solution. It references several of the development projects. The reason it is separate is to avoid interference with the development solution's unit test VSMDI file. And to allow us to play with different execution methods (other test runners, like Gallio or StoryTeller) without interfering with the development solution. Recently, an interface changed in the development solution, one of our test mocks implemented that interface. But, it was not updated because there was no warning at compile time because it was in another solution. This broke our CI build. Does anyone have a similar setup? How do you handle these issues, do you follow a strict procedure or is there some kind of technical answer?

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  • Implementing a Stack using Test-Driven Development

    - by devoured elysium
    I am doing my first steps with TDD. The problem is (as probably with everyone starting with TDD), I never know very well what kind of unit tests to do when I start working in my projects. Let's assume I want to write a Stack class with the following methods(I choose it as it's an easy example): Stack<T> - Push(element : T) - Pop() : T - Seek() : T - Count : int - IsEmpty : boolean How would you approch this? I never understood if the idea is to test a few corner cases for each method of the Stack class or start by doing a few "use cases" with the class, like adding 10 elements and removing them. What is the idea? To make code that uses the Stack as close as possible to what I'll use in my real code? Or just make simple "add one element" unit tests where I test if IsEmpty and Count were changed by adding that element? How am I supposed to start with this?

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  • Are these good interview questions for Flex developer?

    - by Ivan Belov
    I am responsible for creating a team, which will build a Flex application. Unfortunately I have zero experience with Flex. So I found an expert within our company to interview candidates. Our expert came up with the following questions: how to write item renderers explain methods commitProperties, updateDisplayList, measure binding positive / negative parts, problems with binding what is ClassFactory ? And why is it needed ? how callLater works ? what is layoutChrome ? what is skin ? did you use autogeneration for Java backend ? how to override managers ? like PopupManager . These sound a little too specific for my taste. Would you say they are decent questions? Is it fair to say, for example, that if Flex developer does not know how to write item renderer, he has very little knowledge of Flex?

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  • how to store BigInteger values in oracle database.

    - by Bipul
    I have connected Java program to Oracle database using JDBC. I want to store BigInteger values(512 bits) in the database. What should be the type of the column? I m trying like this: I have taken a column of number type in the database. I converted BigInteger to BigDecimal like this: BigInteger b=new BigInteger("5779857570957802579079"); Number n =b; BigDecimal d=(BigDecimal)n; PreparedStatement pstmt=con.prepareStatemant("insert into database values(?,?)"); pstmt.setString(1,"john"); pstmt.setBigDecimal(2,d); I am getting the following exception: javax.servlet.ServletException: java.lang.ClassCastException: java.math.BigInteger cannot be cast to java.math.BigDecimal root cause java.lang.ClassCastException: java.math.BigInteger cannot be cast to java.math.BigDecimal Is there anything wrong in this code snippet? If there is, please suggest other methods.

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  • AS3 Event Bubbling outside of the Scenegraph/DisplayList

    - by Brian Heylin
    Hi just wondering if it is possible to take advantage of event bubbling in non display list classes in AS3. For example in the model of an application where there is a City class that contains many Cars. What methods are there to attach an event listener to a City object and receive events that bubble up from the child Cars. To clarify The City and Car objects are not part of the display list, they are not DisplayObjects. So can bubbling be implemented outside of the display list somehow? As far as I know, this is not possible without manually attaching event listeners to each Car object and re dispatching the event from the City object. Anyone else have a cleaner solution?

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  • Refferenced by projects .net 4.0 assemblies have no IL. How? and What for?

    - by er-v
    There is something I don't understand. Today I desided to find out what is inside Sistem.Web.dll version 4.0.0.0 So I decided to find the place where this assembly located. and opened this assembly with reflector - all methods were empty - and then with ilDasm from 7.0 SDK. This what I saw After some research I've found fullfeatured assemblies in gac. Actualy here C:\Windows\assembly\NativeImages_v4.0.30319_32\System.Web\82087f17d3b3f9c493e7261d608a6af4 They are much larger in size. So why does references goes not to the gac, but to the C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\ Why don't they have IL inside? How does it works? Mabe I don't understand something.

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  • [three20] dynamically add Items to TTLauncher

    - by choise
    Hi guys, in my app i got a TTLauncher Object with some TTLauncherItems in it. Now i want to add some Items dynamically inside my App by pressing a button. Is there a simple way to do that or do i have to create my own methods? In the original facebook application there is already something like that implemented. (You can add your Friends to the Launcher) If not, what would be the best thing to do something like that? Store all "extra items" in a plist oder even in a database and query them, each time TTLauncher object is initialized? Thanks for help :)

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  • JLabel with separate text and icon background colours

    - by emeraldjava
    Hey, I have a simple Jlabel element with text and icon setting the background changes the full label colour. I want to be able to only render the background colour on the text section of the label, ie - to have separate backgrounds/foregrounds for the icon and text. Selecting/deselecting the label will flip the colour behind the icon and text. Is this possible to do this by just extending JLabel, and if so which methods should i be looking to customise? My alternative idea is to create a panel with two separate label elements, one with an icon the other with text. It seems a bit messy, and before i start i'm wondering is there a smarter way of achieving this with Swing.

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  • ASP/NET MVC: Test Controllers w/Sessions? Mocking?

    - by Codewerks
    I read some of the answers on here re: testing views and controllers, and mocking, but I still can't figure out how to test an ASP.NET MVC controller that reads and sets Session values (or any other context based variables.) How do I provide a (Session) context for my test methods? Is mocking the answer? Anybody have examples? Basically, I'd like to fake a session before I call the controller method and have the controller use that session. Any ideas?

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  • Method chaining and exceptions in C#

    - by devoured elysium
    If I have a method chain like the following: var abc = new ABC(); abc.method1() .method2() .methodThrowsException() .method3() ; assuming I've defined method1(), method2() and method3() as public ABC method1() { return this; } and methodThrowsException() as public ABC method3() { throw new ArgumentException(); } When running the code, is it possible to know which specific line of code has thrown the Exception, or will it just consider all the method chaining as just one line? I've done a simple test and it seems it considers them all as just one line but Method Chaining says Putting methods on separate lines also makes debugging easier as error messages and debugger control is usually on a line by line basis. Am I missing something, or does that just not apply to C#? Thanks

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