查看函数调用链

最近在学twisted，它的event loop嵌套很深，有什么方法查看回调函数是怎样被调用的吗？
可以在回调函数里面调用traceback.print_stack()，如下图所示，而且也不会中断代码的运行：

import traceback

def stack():
    print 'The python stack:'
    traceback.print_stack()

from twisted.internet import reactor
reactor.callWhenRunning(stack)
reactor.run()

输出结果如下(most recent call last)：

The python stack:
  File "/Users/thomas_young/Documents/git_download/introduction-python/twisted-intro-master/basic-twisted/stack.py", line 10, in 
    reactor.run()
  File "/Library/Python/2.7/site-packages/twisted/internet/base.py", line 1266, in run
    self.startRunning(installSignalHandlers=installSignalHandlers)
  File "/Library/Python/2.7/site-packages/twisted/internet/base.py", line 1246, in startRunning
    ReactorBase.startRunning(self)
  File "/Library/Python/2.7/site-packages/twisted/internet/base.py", line 759, in startRunning
    self.fireSystemEvent('startup')
  File "/Library/Python/2.7/site-packages/twisted/internet/base.py", line 710, in fireSystemEvent
    event.fireEvent()
  File "/Library/Python/2.7/site-packages/twisted/internet/base.py", line 434, in fireEvent
    DeferredList(beforeResults).addCallback(self._continueFiring)
  File "/Library/Python/2.7/site-packages/twisted/internet/defer.py", line 322, in addCallback
    callbackKeywords=kw)
  File "/Library/Python/2.7/site-packages/twisted/internet/defer.py", line 311, in addCallbacks
    self._runCallbacks()
  File "/Library/Python/2.7/site-packages/twisted/internet/defer.py", line 654, in _runCallbacks
    current.result = callback(current.result, *args, **kw)
  File "/Library/Python/2.7/site-packages/twisted/internet/base.py", line 447, in _continueFiring
    callable(*args, **kwargs)
  File "/Users/thomas_young/Documents/git_download/introduction-python/twisted-intro-master/basic-twisted/stack.py", line 6, in stack
    traceback.print_stack()