Update cnn_classification.py

[rohan472000]

Describe your change:

• Add an algorithm?
  [x]Fix a bug or typo in an existing algorithm?
• Documentation change?

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.

• 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.
  [x] All function parameters and return values are annotated with Python type hints.
  [x] All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.

[cclauss]

Nice!