ModuleNotFoundError: No module named 'X'

This error occurs when the Python interpreter cannot find the library you are trying to import. This usually means the package isn't installed in your current environment (venv) or you have a typo in the import name.

• Package not installed in the active virtual environment
• Typo in the package name (e.g. 'sklearn' vs 'scikit-learn')
• Mismatch between install name and import name (e.g. 'yaml' vs 'PyYAML')
• Operating in the wrong virtual environment