ap, f107 checks in hwm.py

[grawe]

In the ap / f017 parameter checking inside of the run function (hwm.py), e.g.,

    # HWM14:
    elif version == 2014:
        if not ap:
            raise ValueError(
                "Must supply ap for HWM14"
            )
        self._run_hwm14(location_time, ap)

the checks are done using 'if not ap', etc. Since "not 0.0" is True in Python, won't this lead to erroneous raises when, for example, ap = 0.0? Would it be better to use "if ap is None"?

[bharding512]

Agreed on "if ap is None" or maybe something that includes nan like np.isfinite().

I thought I had always implemented pure HWM (i.e., not including DWM) in my code by setting ap=0.0. Maybe I'm remembering that incorrectly. Unfortunately there's a large blackout in the bay area right now and all of our servers are offline so I can't check.