documentation in metadata

Can we document what we do in the nc attrs?

when we save skill to skill.nc, we could add the way how we calculated the skill in the nc attributes. To be seen in a terminal with ncdump -h

similar: https://github.com/NCAR/esmlab/blob/master/esmlab/utils/_variables.py

def get_original_attrs(x):
    attrs = x.attrs.copy()
    encoding = x.encoding
    if "_FillValue" not in encoding:
        encoding["_FillValue"] = None
    return attrs, encoding


def update_attrs(x, original_attrs, original_encoding):
    for att in ["grid_loc", "coordinates"]:
        if att in original_attrs:
            del original_attrs[att]

    x.attrs = original_attrs
    x.encoding = {
        key: val
        for key, val in original_encoding.items()
        if key in ["_FillValue", "dtype"]
    }
return x

[aaronspring]

we can make the URL persist, when we dont change. and a broken link to an existing package is I think better than non.

skill.attrs['documentation'] = some_link_to_readthedocs or wiki page where PM or hindcast philosophy is explained
skill.attrs['best skill'] = 0
skill.attrs['worst skill'] = inf

[aaronspring]

optional: when bootstrapped results sig number of bootstrap