* lisp/progmodes/python.el:

* lisp/progmodes/python.el:
(python-nav--lisp-forward-sexp): New function.
(python-nav--lisp-forward-sexp-safe): Use it.  Rename from
python-nav-lisp-forward-sexp-safe.
(python-nav--forward-sexp): New argument SAFE allows switching
forward sexp movement behavior for parens.
(python-nav-forward-sexp): Throw errors on unterminated parens.
(python-nav-backward-sexp, python-nav-forward-sexp-safe)
(python-nav-backward-sexp-safe): New functions.
(python-shell-buffer-substring): Use
`python-nav-forward-sexp-safe'.

* test/automated/python-tests.el
(python-nav-lisp-forward-sexp-safe-1): Remove test.
(python-nav-forward-sexp-safe-1): New test.