Danb27/sar literal fix

[danb27]

Description

Change how the package checks for similarity type from 'is' to ==
This is more correct python code - check for the same value in the string using ==, avoids problems when unpacking parameters from other files using json package.

Related Issues

Checklist:

• I have followed the contribution guidelines and code style for this project.
• I have added tests covering my contributions.
• I have updated the documentation accordingly.
• This PR is being made to staging branch and not to main branch.

[ghost]

All CLA requirements met.

[danb27]

More information on the problem with using 'is': https://lerner.co.il/2015/06/16/why-you-should-almost-never-use-is-in-python/

[gramhagen]

good catch!

[miguelgfierro]

Great work!

[miguelgfierro]

hey @danb27 I have just realized that you haven't signed your commits, so your name won't appear on GitHub. If you want to keep contributing to the repo and that your name appears on it, you can sign your commits following: https://github.com/microsoft/recommenders/wiki/How-to-add-your-name-as-a-contributor-to-the-repo#make-sure-that-your-github-user-is-setup-correctly

git config --global user.name "Your Name"
git config --global user.email your-github-username@users.noreply.github.com