This pull request adds a new method called `calculate_pricing` to the
`GPT4Brain` class in the codebase. This method calculates the pricing
for the GPT4Brain model. Additionally, the user usage in the chat
controller has been updated to include the new pricing calculation
method.
moved to brains
# Description
Please include a summary of the changes and the related issue. Please
also include relevant motivation and context.
## Checklist before requesting a review
Please delete options that are not relevant.
- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented hard-to-understand areas
- [ ] I have ideally added tests that prove my fix is effective or that
my feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged
## Screenshots (if appropriate):
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Co-authored-by: Antoine Dewez <44063631+Zewed@users.noreply.github.com>
