def __repr__(self):
        return "<NamedRequirements({}{})>".format(
            self.name,
            ", filename='{}'".format(self.filename.name) if self.filename
            else "")
def _read_flow(self, file_name):
        # Return the flow or a tuple with the flow and the valid_flow_mask if _has_builtin_flow_mask is True
        pass