title: Vim — running external command bound to F5 to run Python script results in error
body: <p>I added the following to my .vimrc file:</p>
  
  <pre><code>nnoremap &lt;silent&gt; &lt;F5&gt;!python %
  </code></pre>
  
  <p>That should run the current file in Python when I press F5. Instead, it gives the following error:</p>
  
  <pre><code>Trackback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
    File "&lt;string&gt;", line 349, in f_with_update
    File "&lt;string&gt;", line 358, in run_this file
  NameError: global name 'send' is not defined
  Press Enter or type command to continue
  </code></pre>
  
  <p>If I re-mapped F5 manually everytime I run VIM, this command works:</p>
  
  <pre><code>:map &lt;silent&gt; &lt;F5&gt;!python %
  </code></pre>
  
  <p>I don't recall mapping anything to F5, and my .vimrc file doesn't contain any mapper.
  Any idea what's happening?</p>