Return a datetime set to be the last of some unit of time given by unit. Acceptable values for unit are "month", "quarter", and "year".

Week days may also be passed to this function. Setting the unit to 'month' and the week day to 'monday' will return the last Monday of the month, for example.

Times are stripped from the input datetime.

Arguments:

def datetime.last_of(
  dt: <datetime> = None,
  unit: <str> = None, # 'quarter', 'month', or 'year'
  day_of_week: <str> = None, # 'monday', 'tuesday', ...
):

Returns <datetime>.

Example:

long_long_ago = datetime.from_date_and_time(
  year=1995,
  month=1,
  day=15,
  hour=0,
  minute=0,
  second=0)
  
# end_of_1995 == December 31 1995 23:59:59
end_of_1995 = datetime.last_of(dt=long_long_ago, unit='year')

# last_monday_1995 == Monday December 25 1995 00:00:00
last_monday_1995 = datetime.last_of(dt=long_long_ago, unit='year',
  day_of_week='monday')