Describe your change:

Adding type annotations for the greater and lesser list types in the algorithm

Checklist:

• [x ] I have read CONTRIBUTING.md.
• [x ] This pull request is all my own work -- I have not plagiarized.
• [x ] I know that pull requests will not be merged if they fail the automated tests.
• [x ] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [x ] All new Python files are placed inside an existing directory.
• [x ] All filenames are in all lowercase characters with no spaces or dashes.
• [x ] All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• [x ] All functions have doctests that pass the automated testing.
• [x ] All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.