Made api's compatible with python3.7+

[bharatjetti]

Description

Tensorflow_models not working when imported in python 3.9 Environment. Added functionality to make the code backward compatible from Python3.7.

• Python 3.9 is not compatible with | operator, which is introduced in Python3.10.
• The typing package need to be used to implement the | functionality in Python3.9.

Reference github issue #11247 #11256

Type of change

For a new feature or function, please create an issue first to discuss it with us before submitting a pull request.

Note: Please delete options that are not relevant.

• [x] Bug fix (non-breaking change which fixes an issue)

Tests

Test Configuration:

Checklist

• [x] I have signed the Contributor License Agreement.
• [x] I have read guidelines for pull request.
• [x] My code follows the coding guidelines.
• [x] I have performed a self code review of my own code.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] I have made corresponding changes to the documentation.
• [x] My changes generate no new warnings.
• [x] I have added tests that prove my fix is effective or that my feature works.