def __repr__(self):
        return "<Requirement(package={package}, version='{version}')>".format(
            package=self.package, version=self.version)
def message_data(self):
        if self.proto_view == 0:
            return self.message.plain_bits_str
        elif self.proto_view == 1:
            return self.message.plain_hex_str
        elif self.proto_view == 2:
            return self.message.plain_ascii_str
        else:
            return None