code: def iter_shuffled(X, columns_to_shuffle=None, pre_shuffle=False,
                    random_state=None):
      
      rng = check_random_state(random_state)
  
      if columns_to_shuffle is None:
          columns_to_shuffle = range(X.shape[1])
  
      if pre_shuffle:
          X_shuffled = X.copy()
          rng.shuffle(X_shuffled)
  
      X_res = X.copy()
      for columns in columns_to_shuffle:
          if pre_shuffle:
              X_res[:, columns] = X_shuffled[:, columns]
          else:
              rng.shuffle(X_res[:, columns])
          yield X_res
          X_res[:, columns] = X[:, columns]
docs: Return an iterator of X matrices which have one or more columns shuffled.
      After each iteration yielded matrix is mutated inplace, so
      if you want to use multiple of them at the same time, make copies.
  
      ``columns_to_shuffle`` is a sequence of column numbers to shuffle.
      By default, all columns are shuffled once, i.e. columns_to_shuffle
      is ``range(X.shape[1])``.
  
      If ``pre_shuffle`` is True, a copy of ``X`` is shuffled once, and then
      result takes shuffled columns from this copy. If it is False,
      columns are shuffled on fly. ``pre_shuffle = True`` can be faster
      if there is a lot of columns, or if columns are used multiple times.