After further testing, I find
ipython somehow not working? is usefull.
And if someone like me want to use the ipython, here is the way:
open src\calibre\utils\ipython.py, add sys.path.extend([the path you got]) neer the top of this file, but after import os, re, sys , then we can use
from calibre import ipython
ipython(locals())
to open ipython again.