code: def _pickle_load(path):
          
          _, ext = os.path.splitext(path)
          topology = None
          if sys.version_info.major == 2:
              if ext == '.pickle2':
                  with open(path, 'rb') as f:
                      topology = pickle.load(f)
              elif ext in ('.pickle3', '.pickle'):
                  with open(path, 'rb') as f:
                      topology = pickle.load(f, protocol=3)
          elif sys.version_info.major == 3:
              if ext == '.pickle2':
                  with open(path, 'rb') as f:
                      topology = pickle.load(f)
              elif ext in ('.pickle3', '.pickle'):
                  with open(path, 'rb') as f:
                      topology = pickle.load(f)
          if topology is None:
              raise ValueError('File {} is not compatible with this version'.format(path))
          return topology
docs: Loads pickled topology. Careful with Python versions though!