title: python throwing an error when I am trying to retrieve tweets based on specific terms from specific users
body: <pre><code>from __future__ import unicode_literals
  import tweepy
  consumer_key='xyz',
  consumer_secret='xyz',
  access_key='xyz',
  access_secret='xyz'
  auth = tweepy.OAuthHandler(consumer_key, consumer_secret)
  auth.set_access_token(access_key, access_secret)
  api=tweepy.API(auth)
  class CustomStreamListener(tweepy.StreamListener):
      def on_status(self, status):
          return True
  sapi = tweepy.streaming.Stream(auth, CustomStreamListener())
  list_users = ['17006157','59145948','157009365','16686144','68044757','33338729']   #Some ids
  list_terms = ['abc','def']   #Some terms
  sapi.filter(follow=list_users, track=list_terms)
  </code></pre>
  
  <p>The output on the python shell is</p>
  
  <pre><code>Traceback (most recent call last):
    File "C:/Python27/nytimes/20052014/mutliple keyword from multiple user search.py", line 44, in &lt;module&gt;
      sapi.filter(track=["list_terms"])
    File "build\bdist.win32\egg\tweepy\streaming.py", line 313, in filter
      self._start(async)
    File "build\bdist.win32\egg\tweepy\streaming.py", line 235, in _start
      self._run()
    File "build\bdist.win32\egg\tweepy\streaming.py", line 151, in _run
      timeout=self.timeout, stream=True, auth=auth)
    File "C:\Python27\lib\site-packages\requests-2.1.0-py2.7.egg\requests\sessions.py", line 348, in request
      prep = self.prepare_request(req)
    File "C:\Python27\lib\site-packages\requests-2.1.0-py2.7.egg\requests\sessions.py", line 286, in prepare_request
      hooks=merge_hooks(request.hooks, self.hooks),
    File "C:\Python27\lib\site-packages\requests-2.1.0-py2.7.egg\requests\models.py", line 290, in prepare
      self.prepare_auth(auth, url)
    File "C:\Python27\lib\site-packages\requests-2.1.0-py2.7.egg\requests\models.py", line 469, in prepare_auth
      r = auth(self)
    File "C:\Python27\lib\site-packages\requests_oauthlib-0.4.0-py2.7.egg\requests_oauthlib\oauth1_auth.py", line 63, in __call__
      unicode(r.url), unicode(r.method), r.body or '', r.headers)
    File "build\bdist.win32\egg\oauthlib\oauth1\rfc5849\__init__.py", line 280, in sign
      request.oauth_params.append(('oauth_signature', self.get_oauth_signature(request)))
    File "build\bdist.win32\egg\oauthlib\oauth1\rfc5849\__init__.py", line 112, in get_oauth_signature
      uri, headers, body = self._render(request)
    File "build\bdist.win32\egg\oauthlib\oauth1\rfc5849\__init__.py", line 186, in _render
      headers = parameters.prepare_headers(request.oauth_params, request.headers, realm=realm)
    File "build\bdist.win32\egg\oauthlib\oauth1\rfc5849\utils.py", line 32, in wrapper
      return target(params, *args, **kwargs)
    File "build\bdist.win32\egg\oauthlib\oauth1\rfc5849\parameters.py", line 58, in prepare_headers
      escaped_value = utils.escape(value)
    File "build\bdist.win32\egg\oauthlib\oauth1\rfc5849\utils.py", line 57, in escape
      'Got %s of type %s.' % (u, type(u)))
  ValueError: Only unicode objects are escapable. Got &lt;generator object &lt;genexpr&gt; at 0x03006080&gt; of type &lt;type 'generator'&gt;.
  </code></pre>
  
  <p>That is all of it.</p>