def build(self, builder):
        """
        Build XML by appending to builder
        """
        if self.codelist_oid is None:
            raise ValueError("CodeListOID not set.")
        builder.start("FlagValue", dict(CodeListOID=self.codelist_oid))
        builder.data(self.flag_value)
        builder.end("FlagValue")
Build XML by appending to builder