C1_W3_Logistic_Regression Assignment is not getting accepted

I am getting an accuracy of 82% and when I am submitting the assignment I am getting an error in the cell 14 as a feedback. I checked the cell multiple times and it’s passing al the cases then what’s the issue? can someone help ?
Error is - Cell #14. Can’t compile the student’s code. Error: TypeError(“unsupported operand type(s) for +=: ‘NoneType’ and ‘NoneType’”)

It appears that in the 14th code cell in the notebook, you have some “None” values (or references to values returned from functions) that cause the grader to crash.

  • You can’t submit a partially complete notebook.
  • The grader uses a totally different set of data to test your code. Passing the tests in the notebook does not prove your code is perfect. For example, using fixed constant values or global variables will cause problems.