def remove_user_from_group(self, group_name, user_name):
        group = self.get_group(group_name)
        user = self.get_user(user_name)
        try:
            group.users.remove(user)
        except __HOLE__:
            raise IAMNotFoundException("User {0} not in group {1}".format(user_name, group_name))
dataset/ETHPy150Open spulec/moto/moto/iam/models.py/IAMBackend.remove_user_from_group