Update avl_tree.py (#2145)
Update avl_tree.py (#2145)

* Update avl_tree.py

it's true definition of AVL tree,change  left and right rotation,and add avl_tree doctest

* Update avl_tree.py

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update data_structures/binary_tree/avl_tree.py

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>

* Update avl_tree.py

update some function name and update doctest

* Update avl_tree.py

change some code format to fit flake8 review

Co-authored-by: Christian Clauss <585dd401264c1e46d17ebec1862e5d2a9b6a6c5d@me.com>
TheAlgorithms/Python