old_contents: checkio = lambda d: list(map(list, zip(*d)))
  
  
  #These "asserts" using only for self-checking and not necessary for auto-testing
  def test_function():
      assert checkio([[1, 2, 3],
                      [4, 5, 6],
                      [7, 8, 9]]) == [[1, 4, 7],
                                      [2, 5, 8],
                                      [3, 6, 9]], "Square matrix"
      assert checkio([[1, 4, 3],
                      [8, 2, 6],
                      [7, 8, 3],
                      [4, 9, 6],
                      [7, 8, 1]]) == [[1, 8, 7, 4, 7],
                                      [4, 2, 8, 9, 8],
                                      [3, 6, 3, 6, 1]], "Rectangle matrix"
  
new_contents: # checkio = lambda d: zip(*d)
  checkio = lambda d: list(map(list, zip(*d)))
  
  
  #These "asserts" using only for self-checking and not necessary for auto-testing
  def test_function():
      # assert isinstance(checkio([[0]]).pop(), list) is True, "Match types"
      assert checkio([[1, 2, 3],
                      [4, 5, 6],
                      [7, 8, 9]]) == [[1, 4, 7],
                                      [2, 5, 8],
                                      [3, 6, 9]], "Square matrix"
      assert checkio([[1, 4, 3],
                      [8, 2, 6],
                      [7, 8, 3],
                      [4, 9, 6],
                      [7, 8, 1]]) == [[1, 8, 7, 4, 7],
                                      [4, 2, 8, 9, 8],
                                      [3, 6, 3, 6, 1]], "Rectangle matrix"
  
  
  if __name__ == '__main__':
      test_function()
  
subject: update matrix-transpose.py