code: def trace_memory_usage(self, frame, event, arg):
          
          if event in ('line', 'return') and frame.f_code in self.code_map:
                  lineno = frame.f_lineno
                  if event == 'return':
                      lineno += 1
                  entry = self.code_map[frame.f_code].setdefault(lineno, [])
                  entry.append(_get_memory(os.getpid()))
  
          return self.trace_memory_usage
docs: Callback for sys.settrace