I looked at several tutorials:
https://spotpy.readthedocs.io/en/latest/How_to_link_a_model_to_SPOTPY/
https://spotpy.readthedocs.io/en/latest/Sensitivity_analysis_with_FAST/
https://spotpy.readthedocs.io/en/latest/Calibration_with_SCE-UA/

For all of those the final sentence "The corresponding code is available for download here." links to 404.