docs: def RANGE(start, end, step=None):
      """
      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
      """
      return {'$range': [start, end, step]} if step is not None else {'$range': [start, end]}