code: def _setup_chassis(self):
          
  
          if self._chassis == "3620":
              self._create_slots(2)
          elif self._chassis == "3640":
              self._create_slots(4)
          elif self._chassis == "3660":
              self._create_slots(7)
              self._slots[0] = Leopard_2FE()
docs: Sets up the router with the corresponding chassis
          (create slots and insert default adapters).