I'd like to be able to pull users from a database using either a supplied e-mail address or the user id (an integer). To do this, I have to detect if the supplied string is an integer, or an e-mail. Looking for the fastest way to do this. Thanks.

def __init__(self, data):
    #populate class data
    self._fetchInfo(data)


def _fetchInfo(self, data):
    #If an email
        #SELECT ... WHERE email = 'data'
    #or if a user_id
        #SELECT ... WHERE id = 'data'

    #Fill class attributes 
    self._id = row['id']
    self._email = row['id']
    ...