'Cast to User() class using the email address in values[0].'

def __CastUser(self, values):

    if (len(values) != 1):
        self.__CastError('user', values, 'requires    one    and    only    one    value')
    elif (values[0] is None):
        self.__CastError('user', values, 'must    be    non-null')
    else:
        return users.User(email=values[0], _auth_domain=self.__auth_domain)
