closes issue #756 Count Complete tree nodes

[Ahkam95]

IMPORTANT: Please do not create a Pull Request without an issue.

All Submissions:

• [x] I have read the CONTRIBUTING document.
• [x] My code is written in Python3 and is ending with .py
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• [x] I have checked that my submission does pass the test on LeetCode.com
• [x] Does your filename follow the naming Conventions?
• [x] Have you linked your PR to an Issue?

Closing issues

Put closes #XXXX in your comment to auto-close the issue that your PR fixes (if such).

closes #756

[Ahkam95]

@riwim Thanks brother

[riwim]

Your are welcome.

LGTM now! 👍