code: def _not_in(x, y):
      
      try:
          return ~x.isin(y)
      except AttributeError:
          if is_list_like(x):
              try:
                  return ~y.isin(x)
              except AttributeError:
                  pass
          return x not in y
docs: Compute the vectorized membership of ``x not in y`` if possible,
      otherwise use Python.