.set_moon_phase() can't take a None argument

[spacerest]

>>> ui.set_moon_phase()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/sadie/Projects/moon/moon/dialamoon.py", line 50, in set_moon_phase
    raise e
  File "/home/sadie/Projects/moon/moon/dialamoon.py", line 44, in set_moon_phase
    if datetime.strptime(date, '%Y-%M-%d').year != datetime.strptime(self.moon_datetime_info['time']+'C', '%d %b %Y %H:%M %Z').year:
TypeError: strptime() argument 1 must be str, not None