I used eclipse+pydev as my python ide. I can't find the similar option like java debugger's "hot code replace". 
That is when debugging a python file, I updated the code, and then save the code, it should trigger the hot code replace. Such that, I can see the changes without stop and restart debugging.
Considering a=2, b=102,When I debugging at the line "c=a+b", I changed the line "b=102" to "b=100", and then save the code. I expect now the "b" should be 100 and c should be 102. But, the b is still 102 and c is still 104.
For Eclipse+PyDev, the hot code replace happens automatically too, but it doesn't affect the function you're currently executing (you need to get out of it and then get back in).
This is a shortcoming of Python itself (it's not possible to change the code for the frame that's currently executing and there's no way to drop the execution of the current frame either).
As a note, you can use the set next statement action to help you get to some place in the current function to exit it sometimes...
How can I set "hot code replace" when debugging python by pydev