def DAY_OF_WEEK(expression):
return {'<STR_LIT>': expression}<EOL>
Returns the day of the week for a date as a number between 1 (Sunday) and 7 (Saturday).
See https://docs.mongodb.com/manual/reference/operator/aggregation/dayOfWeek/
for more details
:param expression: expression or variable of a Date, a Timestamp, or an ObjectID
:return: Aggregation operator