Timestamp.fromtimestamp(0) currently returns Timestamp(‘1969-12-31 19:00:00’) here on the east coast of the US since it uses the system’s time zone information. Perhaps the author meant
start = pd.Timestamp(0).strftime(’%Y-%m-%d’)
which sets start to ‘1970-01-01’
Thanks for the book. So far it showed me that a couple of assumptions I had about how pandas works were incorrect.