os.stat returns st_mtime and st_ctime attributes, the modification time is st_mtime and st_ctime "change time" on POSIX.
is there any function that return the creation time of a file using python and under Linux?
What do you mean it can't be done [1]? The function, os.stat(path).st_birthtime, works great.

[1]:
Somebody said that it couldn’t be done
      But he with a chuckle replied
That “maybe it couldn’t,” but he would be one
      Who wouldn’t say so till he’d tried.
So he buckled right in with the trace of a grin
      On his face. If he worried he hid it.
He started to sing as he tackled the thing
      That couldn’t be done, and he did it!
-- Edgar Albert Guest
Get file creation time with Python on linux