title: Fixing Python requests.exception.InvalidURL : Invalid percent-escape sequence 'u2' error?
body: <p>My python app accepts url's processed using Javascript <code>escape</code> function which are <code>unescaped</code> using <code>urllib.unquote</code> in my python code, this works fine for most url's but fails if the file-name (which is also part of the url) contains a <code>&amp;</code> in it with following error.</p>
  
  <p><code>requests.exception.InvalidURL : Invalid percent-escape sequence 'u2'</code></p>
  
  <p><strong>Edit: Example code with error</strong></p>
  
  <pre><code>import urllib,requests
  url = "https%3A//r20---sn-cvh7zn76.googlevideo.com/videoplayback%3Fipbits%3D0%26ms%3Dau%26fexp%3D931328%2C931946%2C934804%2C914004%2C931818%2C937417%2C913434%2C923328%2C936916%2C934022%2C936923%26sparams%3Dclen%2Cdur%2Cgir%2Cid%2Cip%2Cipbits%2Citag%2Clmt%2Crequiressl%2Csource%2Cupn%2Cexpire%26source%3Dyoutube%26mv%3Dm%26dur%3D278.593%26id%3Do-AOxIEhMchATdRjU99Gveow8reeBWtxFaqwpWifXC9KwS%26expire%3D1397662367%26clen%3D4425254%26sver%3D3%26signature%3D9A0CFEC5F59C2C7FC35A8CF87491F4E7F9683C59.C46B3A3602A20611C73CC4228FCB8B287034F52D%26mt%3D1397639060%26upn%3DBknKrHPqCCw%26gir%3Dyes%26itag%3D140%26key%3Dyt5%26ip%3D117.200.252.163%26lmt%3D1386126879207085%26requiressl%3Dyes%26ratebypass%3Dyes%26title%3DHum%20Tuhmaray%20hain%20%u2022%20SRK%20_%20Madhuri%20Dixit%20%u2022%20HD%201080p%20%u2022%20Hindi%20%u2022%20Bollywood%20Songs"
  url = urllib.unquote_plus(url).decode('utf-8')
  resp = requests.head(url, verify=False, allow_redirects=True)
  print resp
  </code></pre>
  
  <p>The string <code>Hum Tuhmaray hain • SRK &amp; Madhuri Dixit •</code> causes issues, the problem seems to be the unicode bullet character <code>%u2022</code> in the url.</p>