title: Python requests: POST request dropping Authorization header
body: <p>I'm trying to make an API POST request using the Python requests library. I am passing through an <code>Authorization</code> header but when I try debugging, I can see that the header is being dropped. I have no idea what's going on.</p>
  
  <p>Here's my code:</p>
  
  <pre><code>access_token = get_access_token()
  bearer_token = base64.b64encode(bytes("'Bearer {}'".format(access_token)), 'utf-8')
  headers = {'Content-Type': 'application/json', 'Authorization': bearer_token}
  data = '{"FirstName" : "Jane", "LastName" : "Smith"}'
  response = requests.post('https://myserver.com/endpoint', headers=headers, data=data)
  </code></pre>
  
  <p>As you can see above, I manually set the <code>Authorization</code> header in the request arguments, but it is missing the actual request's headers:
  <code>{'Connection': 'keep-alive', 'Content-Type': 'application/json', 'Accept-Encoding': 'gzip, deflate', 'Accept': '*/*', 'User-Agent': 'python-requests/2.4.3 CPython/2.7.9 Linux/4.1.19-v7+'}</code>.</p>
  
  <p>An additional piece of information is that if I change the POST request to a GET request, the <code>Authorization</code> header passes through normally!</p>
  
  <p>Why would this library be dropping the header for POST requests and how do I get this to work?</p>
  
  <p>Using v2.4.3 of the requests lib and Python 2.7.9</p>