As I know, %debug magic can do debug within one cell. However, I have function calls across multiple cells. For example, In[1]: def fun1(a) def fun2(b) # I want to set a breakpoint for the following line # return do_some_thing_about(b) return fun2(a) In[2]: import multiprocessing as mp pool=mp.Pool(processes=2) results=pool.map(fun1, 1.0) pool.close() pool.join What I tried: I tried to set %debug