def METHOD_NAME(cls, file=None):
    """Debug helper to print the ABC registry."""
    print >> file, "Class: %s.%s" % (cls.__module__, cls.__name__)
    print >> file, "Inv.counter: %s" % ABCMeta._abc_invalidation_counter
    for name in sorted(cls.__dict__.keys()):
        if name.startswith("_abc_"):
            value = getattr(cls, name)
            print >> file, "%s: %r" % (name, value)