[ENH] Updated convert_excel_date to throw meaningful error

[nvamsikrishna05]

…ues are of type non-numeric

PR Description

Please describe the changes proposed in the pull request:

• Updated convert_excel_date function to throw meaningful error when input column contains non-numeric data.

**This PR resolves #813 **

PR Checklist

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1. PR in from a fork off your branch. Do not PR from <your_username>:dev, but rather from <your_username>:<feature-branch_name>.

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Automatic checks

There will be automatic checks run on the PR. These include:

• Building a preview of the docs on Netlify
• Automatically linting the code
• Making sure the code is documented
• Making sure that all tests are passed
• Making sure that code coverage doesn't go down.

Relevant Reviewers

Please tag maintainers to review.

• @ericmjl
• @loganthomas
• @samukweku

[samukweku]

@nvamsikrishna05 kindly have a look at the failing checks and resolve

[nvamsikrishna05]

@samukweku I resolved the code formatting and linting check which were failing. Now they are passing. But one of the jupyter notebook is failing at the finance functions which wasn't modified in this pr.

I ran the same notebook in colab and it was running properly for me. Can you help me out with what's the issue ?

[samukweku]

@nvamsikrishna05 for the failing notebook, change current year value to int(x.name)

[nvamsikrishna05]

@samukweku Thanks, it worked. All Tests passed now. If you see there's no other issue you can merge the PR.

[samukweku]

@nvamsikrishna05 lets wait for another team member to review before merging

[nvamsikrishna05]

@samukweku sure. Thanks

[ericmjl]

@nvamsikrishna05, thank you for the contribution, and @samukweku thank you for reviewing the PR! I looked at it and I approve too. Going to hit merge.