def RANGE(start, end, step=None):
return {'<STR_LIT>': [start, end, step]} if step is not None else {'<STR_LIT>': [start, end]}<EOL>
Generates the sequence from the specified starting number by successively
incrementing the starting number by the specified step value up to but not including the end point.
See https://docs.mongodb.com/manual/reference/operator/aggregation/range/
for more details
:param start: An integer (or valid expression) that specifies the start of the sequence.
:param end: An integer (or valid expression) that specifies the exclusive upper limit of the sequence.
:param step: An integer (or valid expression) that specifies the increment value.
:return: Aggregation operator