code: def _reserved(self, P, day):
      max_days = len(self.rooms)
      As = range(0, day)
      return sum(
          self._allocated(P, a, L)
          for a in As
          for L in range(day - a + 1, max_days + 1)
      )
  
file_path: mystic/examples2/hotel_pricing.py
imports: import math
  import mystic
label_desc: Use image node_id 4 for calling the hotel obj's underlying member method code with example usage: obj._reserved(P, day) and returns: sum