code: def _dump_registry(cls, file=None):
          
          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)
docs: Debug helper to print the ABC registry.