def serialize(self):
        """This function serialize into a simple dict object.
        It is used when transferring data to other daemons over the network (http)

        Here we directly return all attributes

        :return: json representation of a Timerange
        :rtype: dict
        """
        return {"hstart": self.hstart, "mstart": self.mstart,
                "hend": self.hend, "mend": self.mend,
                "is_valid": self.is_valid}