'The label is the unique set of identifiers for the object.
Usually, this will include all of the information about the state
*except* the time (in the case of time-dependent objects).
This must be a tuple, rather than a Tuple.'

@property
def label(self):

    if (len(self.args) == 0):
        return self._eval_args(list(self.default_args()))
    else:
        return self.args
