Python flask_login 模块，UserMixin() 实例源码

def get_user(cls, user):
        """Get user object:
        1º check if user is already User, LocalProxy, or AnnonymousUser object
            if so, just return it
        2º if not, search for this user and return if found.
        3º otherwise, return DoesNotExists exception"""
        if any([isinstance(user, obj) for obj in [UserMixin,
                                                  AnonymousUserMixin]]):
            return user
        if isinstance(user, LocalProxy):
            return user._get_current_object()
        try:
            return User.objects.get(username=user)
        except (me.DoesNotExist, me.ValidationError):
            return User.objects.get(id=user)

def __eq__(self, other):
        '''
        Checks the equality of two `UserMixin` objects using `get_id`.
        '''
        if isinstance(other, UserMixin):
            return self.get_id() == other.get_id()
        return NotImplemented

def __ne__(self, other):
        '''
        Checks the inequality of two `UserMixin` objects using `get_id`.
        '''
        equal = self.__eq__(other)
        if equal is NotImplemented:
            return NotImplemented
        return not equal