trading calendar error with alpaca ingest

[Leukos653]

Any advice on how to resolve this would be ++appreciated. Thanks!
Andy

Here's my order in the terminal:
(zipline) (base) my-macbookie:zipline-trader andy$ python zipline/data/bundles/alpaca_api.py

Here's the error:
Traceback (most recent call last):
File "zipline/data/bundles/alpaca_api.py", line 11, in
from trading_calendars import TradingCalendar
File "/Users/andy/zipline/lib/python3.7/site-packages/trading_calendars/init.py", line 16, in
from .trading_calendar import TradingCalendar
File "/Users/andy/zipline/lib/python3.7/site-packages/trading_calendars/trading_calendar.py", line 33, in
from .calendar_helpers import (
File "/Users/andy/zipline/lib/python3.7/site-packages/trading_calendars/calendar_helpers.py", line 6, in
NP_NAT = np.array([pd.NaT], dtype=np.int64)[0]
TypeError: int() argument must be a string, a bytes-like object or a number, not 'NaTType'