python-eval eval python code in the current buffer [Emacs]

test.el

(defun python-eval ()

  " Eval python code in current buffer.
It seems that the default python-mode doesn't have this function"

  (interactive)
  (let ((script-py (buffer-file-name))
        (tmp-script-py "/Users/wenjunyan/.test-code.py")
        (output-buffer "*python-eval-output*"))

    (if script-py
        (progn
          (when (buffer-modified-p)
            (when (y-or-n-p "This buffer is modified. Save it to file ?")
              (save-buffer)))
          (shell-command (concat "python " script-py) output-buffer))

      (write-file tmp-script-py)
      (kill-buffer)
      (shell-command (concat "python " tmp-script-py) output-buffer)
      (delete-file tmp-script-py))))