def is_different(self, prev):
    (removed, added, updated) = self.diff_messages(prev)
    return ((len(removed) != 0) or (len(added) != 0) or (len(updated) != 0))
def is_different(self, prev):
    (removed, added, updated) = self.diff_messages(prev)
    return ((len(removed) != 0) or (len(added) != 0) or (len(updated) != 0))