title: Post Request in Python with a cookie set, but still not sending the datas correctly
body: <p>I am new to Python, but I guess I'm handling the problem not too bad after 3h of research.
  My POST request is bypassing the login wall thanks to the cookie but it never posts the informations I'd like on the page. :(</p>
  
  <p>Here's my code :</p>
  
  <pre><code>import requests
  
  url = "url"
  headers = {
  'Cookie': 'cookie',
  'Content-Type': 'multipart/form-data',
  'Accept': 'text/html,application/xhtml+xml',
  'Accept-Language': 'en-gb,en;q=0.5',
  'Accept-Encoding': 'gzip,deflate',
  'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
  'Keep-Alive': '300',
  'Connection': 'keep-alive',
  'Content-Length': '41'
  }
  
  payload = {
  'seo_page[keyword]': 'test',
  'commit': 'Save'
  }
  
  p = requests.post(url, data=payload, headers=headers)
  
  print p.text.encode('utf8')
  print p.encoding
  print p.headers
  </code></pre>
  
  <p>Which is, I think, exactly what's advised in the 15 topics I've read about how to POST datas on webform page.</p>
  
  <p>print p.text.encode('utf8') gives me the HTML without the datas I'm trying to send.</p>
  
  <p>Any idea? :)</p>
  
  <p>Thank you very much!</p>