`irradiance.detect_clearsky` expects measured and clear-sky GHI to be input as Series, and has an input `times` as a DatetimeIndex. https://github.com/pvlib/pvlib-python/blob/85eeaa795e82bb486bc58488ac70269da8c72be0/pvlib/clearsky.py#L629 What is the use case for having `times` as a separate input? Should the function instead use `measured.index`?