code: def mock(self, slot, rpc_id, value):
          
  
          address = slot.address
  
          if address not in self.mock_rpcs:
              self.mock_rpcs[address] = {}
  
          self.mock_rpcs[address][rpc_id] = value
docs: Store a mock return value for an RPC
  
          Args:
              slot (SlotIdentifier): The slot we are mocking
              rpc_id (int): The rpc we are mocking
              value (int): The value that should be returned
                  when the RPC is called.