title: Can't save file: "autopep8 command not found"
body: <p>I'm running python in emacs. I've written some code, and now I go to save the code using <code>C-x C-s</code> as normal. However, instead of saving, <code>autopep8 command not found</code> appears in the minibuffer. I can't save my code. </p>
  
  <p>What can I do to restore function to emacs and save my file?</p>
  
  <p>Here is my init.el</p>
  
  <pre><code>;; init.el --- Emacs configuration
  
  ;; INSTALL PACKAGES
  ;; --------------------------------------
  
  (require 'package)
  
  (add-to-list 'package-archives '("melpa" . "http://melpa.org/packages/") t)
  (add-to-list 'package-archives '("marmalade" . "https://marmalade-repo.org/packages/"))
  
  (package-initialize)
  (when (not package-archive-contents)
    (package-refresh-contents))
  
  (defvar myPackages
    '(better-defaults
      paredit
      idle-highlight-mode
      ido-ubiquitous
      find-file-in-project
      smex
      scpaste
      ein
      elpy
      flycheck
      material-theme
      py-autopep8))
  (package-refresh-contents)
  
  (mapc #'(lambda (package)
      (unless (package-installed-p package)
        (package-install package)))
        myPackages)
  
  ;; BASIC CUSTOMIZATION
  ;; --------------------------------------
  
  (setq inhibit-startup-message t) ;; hide the startup message
  (load-theme 'material t) ;; load material theme
  (global-linum-mode t) ;; enable line numbers globally
  
  ;; PYTHON CONFIGURATION
  ;; --------------------------------------
  
  (elpy-enable)
  (elpy-use-ipython)
  
  ;; use flycheck not flymake with elpy
  (when (require 'flycheck nil t)
    (setq elpy-modules (delq 'elpy-module-flymake elpy-modules))
    (add-hook 'elpy-mode-hook 'flycheck-mode))
  
  ;; enable autopep8 formatting on save
  (require 'py-autopep8)
  (add-hook 'elpy-mode-hook 'py-autopep8-enable-on-save)
  
  ;; init.el ends here
  </code></pre>