When I modify a spine, the "modified" value seems wrong

[cudmore]

Followup to issue 3. When I modify a spine, the "modified" date does not seem correct?

I get modified as 2024-03-20 01:40:25 but today is 2024-03-19 18:46:00?

It seems to be here in the code:

df.loc[id, "modified"] = np.datetime64("now")

If I import datetime and switch that to

        df.loc[id, "modified"] = np.datetime64(datetime.datetime.now())

I get the correct local current time, like 2024-03-19 18:48:38.720617.