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Wrong Return in documentation of cloud_covr_to_transmittance_linear

See original GitHub issue

In the documentation of the pvlib.forecast.NDFD.cloud_cover_to_transmittance_linear function, it seems the documented return is the wrong one: It shows the GHI as the return instead of the transmittance.

Here is the function in pvlib.forecast that seems to confirm the case.

    """
    Convert cloud cover to atmospheric transmittance using a linear
    model.

    0% cloud cover returns offset.

    100% cloud cover returns 0.

    Parameters
    ----------
    cloud_cover : numeric
        Cloud cover in %.
    offset : numeric, default 0.75
        Determines the maximum transmittance.
    kwargs
        Not used.

    Returns
    -------
    ghi : numeric
        Estimated GHI.
    """
    transmittance = ((100.0 - cloud_cover) / 100.0) * offset

    return transmittance`