* perfect code

* delete __all__

* refine program translator

* fix warning: not override

* fix bug

* merge new modifications

* modify by reviews

* resolve conflicts

* resolve conflicts

* fix

* fix

* fix conflicts

* pseudocode of backward

* modify test

* modify register op

* clear other code

* modify ci build bug

* reply review comments

* reply review comments

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Co-authored-by: Nkangguangli <kangguangli@hotmail.com>

* support construct network using ir in Python

* fix py3 bugs

* change source return type to OpResult