Fix type issues in math_utils.py

[jackgerrits]

Why are these changes needed?

Related issue number

#1462

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (5b217c9) 34.24% compared to head (5b88ccc) 40.43%.

Files	Patch %	Lines
autogen/math_utils.py	92.85%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1544      +/-   ##
==========================================
+ Coverage   34.24%   40.43%   +6.18%     
==========================================
  Files          42       42              
  Lines        5098     5105       +7     
  Branches     1165     1234      +69     
==========================================
+ Hits         1746     2064     +318     
+ Misses       3209     2852     -357     
- Partials      143      189      +46     

Flag	Coverage Δ
unittests	40.41% <92.85%> (+6.16%)	⬆️

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[sonichi]

This file is currently not covered by test. It was covered by a test for a functionality only supported using the old openai completion api. We haven't migrated that functionality to v0.2. We might either migrate it or remove it. So, please avoid making changes in these files before that decision is made.

[jackgerrits]

In that case should we ignore type checking in this file? If so, I will add it to the exclusions list in #1543 and close this