'Should merge the state plugin with the provided others.
:param others: the other state plugin
:param merge_conditions: a symbolic condition for each of the plugins
:param common_ancestor: a common ancestor of this plugin and the others being merged
:returns: a merged plugin
:rtype: SimStatePlugin'

def merge(self, others, merge_conditions, common_ancestor=None):

    raise Exception('merge()    not    implement    for    %s', self.__class__.__name__)
