def __repr__(self):
        return "<NamedRequirements({}{})>".format(
            self.name,
            ", filename='{}'".format(self.filename.name) if self.filename
            else "")
def serialize(self):
        s = []
        for v in self:
            if isinstance(v, BaseConfig):
                v = v.serialize()
            s.append(v)
        return s