human
Solve the following python programming problem given the following code:
def test_on_delete_can_delay_expiration(self) : 
    self.session.expiry = 1 
    self.session.expiry_date = 1 
    def promote(self, forced) : 
        self.promoted = 10 
from types import MethodType 
    self.session.on_delete = MethodType (promote, self.session, SessionFake) 
    self.sc.add (promote.session) 
    self.sc.expire (current_time = 5) 
    self.assertTrue (self._check_session_is_in_items ()) 
    self.assertTrue (self._check_session_is_in_queue ()) 

    
    

    Fix the buggy line: self.sc.add (promote.session)
assistant
#Here is Python code to fix the buggy line: self.

self.sc.add (self.session)