title: Python requests sending Content-Length 0 in POST request
body: <p>Is it really what it should be or is there some problem?</p>
  
  <p>I am doing it simply as it is mentioned in the doc like this:</p>
  
  <pre><code>response = requests.post(path, client_id=self.app_id, client_secret=self.app_secret, grant_type="client_credentials")
  </code></pre>
  
  <p>Output of <code>response.request.headers</code> is</p>
  
  <pre><code>{'Content-Length': '0', 'User-Agent': 'python-requests/2.4.1 CPython/2.7.5 Darwin/13.3.0', 'Connection': 'keep-alive', 'Accept': '*/*', 'Accept-Encoding': 'gzip, deflate'}
  </code></pre>
  
  <p>What is the error I am doing?</p>