def get_schema(self, schema: object) -> object:
    """Get the Schema class
    """
    if isinstance(schema, str):
        Schema = getattr(self.request["operation"], schema, None)
    else:
        Schema = schema
    if Schema is None:
        Schema = getattr(self, schema, None)
        if Schema is None:
            raise web.HTTPNotImplemented
    return Schema