title: requests python lib adding in Accept header
body: <p>so I have made a request to a server with pythons request library. The code looks like this (it uses an adapter so it needs to match a certain pattern)</p>
  
  <pre><code>def getRequest(self, url, header):
      """
      implementation of a get request
      """
  
      conn = requests.get(url,  headers=header)
      newBody = conn.content
      newHeader = conn.headers
      newHeader['status'] = conn.status_code
  
      response  = {"Headers" : newHeader, "Body" : newBody.decode('utf-8')}
  
      self._huddleErrors.handleResponseError(response)
      return response
  </code></pre>
  
  <p>the header parameter I am parsing in is this</p>
  
  <pre><code>{'Authorization': 'OAuth2 handsOffMyToken', 'Accept': 'application/vnd.huddle.data+json'}
  </code></pre>
  
  <p>however I am getting an xml response back from the server. After checking fiddler I see the request being sent is:</p>
  
  <pre><code>Accept-Encoding: identity
  Accept: */*
  Host: api.huddle.dev
  Authorization: OAuth2 HandsOffMyToken
  Accept: application/vnd.huddle.data+json
  Accept-Encoding: gzip, deflate, compress
  User-Agent: python-requests/1.2.3 CPython/3.3.2 Windows/2008ServerR2
  </code></pre>
  
  <p>As we can see there are 2 Accept Headers! The requests library is adding in this Accept:* / * header which is throwing off the server. Does anyone know how I can stop this?</p>