docs: def stack_suffix(self, context_sensitivity_level):
          """
          Generate the stack suffix. A stack suffix can be used as the key to a SimRun in CFG recovery.
  
          :param int context_sensitivity_level: Level of context sensitivity.
          :return: A tuple of stack suffix.
          :rtype: tuple
          """
  
          ret = ()
  
          for frame in self:
              if len(ret) >= context_sensitivity_level*2:
                  break
              ret = (frame.call_site_addr, frame.func_addr) + ret
  
          while len(ret) < context_sensitivity_level*2:
              ret = (None, None) + ret
  
          return ret