@abc.abstractmethod<EOL><INDENT>def is_implicit(self):<DEDENT>
return<EOL>
Tests if this event is implicit.

        An implicit event is one that is generated from an offset or
        recurring series.

        :return: ``true`` if this event is implicit, ``false`` if explicitly defined
        :rtype: ``boolean``

        *compliance: mandatory -- This method must be implemented.*