* [CodeStyle] remove all future import

* revert test_error.py

* restore future import in example code

[CodeStyle] use np.testing.assert_array_equal instead of self.assertTrue(np.array_equal(...)) (#44947)

* automatically fix

* update comments

* numpy -> np

* self.assertEqual(..., True)

* wrong usage (err_msg=True)

这不是修复导致的错误，这些是原来 `self.assertTrue(..., True)`
的错误用法，因此在修复后将其认为位置参数 `err_msg`

* some missing fix

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* add unbind yaml

* fix unittest

* add transpose unbind

* add unittest

* refine transpose unittest

* add unbind pyhon api. test=develp

* add unbind op
unbind(tensor, dim=0):
说明：移除指定维后，返回一组数组，包含了沿着指定维切片后的各个切片。

tensor(Tensor) -- 输入Tensor
dim(int) -- 删除的维度

示例：
 Input = [[1,2],
           [3,4],
           [5,6]]
  axis = 0
  Output[0] = [1,2]
  Output[1] = [3,4]
  Output[2] = [5,6]