def authenticate(email=None, password=None):
    """
    Authenticates the user based on the email field 
    and sets the backend information
    """
    try:
        backend = EmailBackend()
        user = backend.authenticate(email=email, password=password)
    except __HOLE__:
        # This backend doesn't accept these credentials 
        # as arguments. Try the next one.
        return None
    # Annotate the user object with the path of the backend.
    if user:
        user.backend = "%s.%s" % (
            backend.__module__, 
            backend.__class__.__name__
        )
    return user
dataset/ETHPy150Open jjdelc/django-easy-registration/easyreg/backends.py/authenticate