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Added new features
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- Added asymmetric choice models.
- Added nested logit and mixed logit models.
- Added tests for mixed logit models.
- Added an example notebook demonstrating how to estimate the mixed logit model.
Improved Documentation
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- Changed documentation to numpy doctoring standard.
Trivial/Internal Changes
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- Made print statements compatible with python3.
- Fixed typos in library documentation.
- Internal refactoring.