def __repr__(self):
        return "<NamedRequirements({}{})>".format(
            self.name,
            ", filename='{}'".format(self.filename.name) if self.filename
            else "")
def serialize(self, value, display=False):
        if not value:
            return ""
        return "\n  " + "\n  ".join(encode(v) for v in value if v)