code: def _lookup(cls: str) -> LdapObjectClass:
      
      if isinstance(cls, str):
          module_name, _, name = cls.rpartition(".")
          module = importlib.import_module(module_name)
          try:
              cls = getattr(module, name)
          except AttributeError:
              raise AttributeError("%s reference cannot be found" % cls)
      return cls
docs: Lookup module.class.