Sets up the router with the corresponding chassis
        (create slots and insert default adapters).

def _setup_chassis(self):
        """
        Sets up the router with the corresponding chassis
        (create slots and insert default adapters).
        """

        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()