def identifier_augment(self):
""" Override this method to define an identifier in lieu of one explicity set.
One must also override :meth:`defined_augment` to return True whenever
this method could return a valid identifier.
:exc:`~yarom.graphObject.IdentifierMissingException` should be
raised if an identifier cannot be generated by this method.
Raises
------
IdentifierMissingException
"""
raise IdentifierMissingException(self)