How to use the habanero.habanero_utils.make_ua function in habanero

def make_request(url, ids, format, style, locale, **kwargs):
  type = cn_format_headers[format]

  if format == "citeproc-json":
    url = "http://api.crossref.org/works/" + ids + "/" + type
  else:
    if format == "text":
      type = type + "; style = " + style + "; locale = " + locale
    url = url + "/" + ids

  htype = {'Accept': type}
  head = dict(make_ua(), **htype)
  response = requests.get(url, headers = head, allow_redirects = True, **kwargs)

  # Raise an HTTPError if the status code of the response is 4XX or 5XX
  response.raise_for_status()

  # set encoding
  response.encoding = "UTF-8"
  return response.text

if works:
        res = Request(mailto, ua_string, url, str(ids[i]) + "/works",
          query, filter, offset, limit, sample, sort,
          order, facet, select, cursor, cursor_max, None, 
          progress_bar, **kwargs).do_request()
        coll.append(res)
      else:
        if agency:
          endpt = url + str(ids[i]) + "/agency"
        else:
          endpt = url + str(ids[i])

        endpt = endpt.strip("/")

        try:
          r = requests.get(endpt, params = payload, headers = make_ua(mailto, ua_string))
          r.raise_for_status()
        except requests.exceptions.HTTPError:
          if is_json(r):
            raise RequestError(r.status_code, parse_json_err(r))
          else:
            r.raise_for_status()
        except requests.exceptions.RequestException as e:
          raise e
        check_json(r)
        js = r.json()
        coll.append(js)

    if len(coll) == 1:
      coll = coll[0]

  return coll

def _req(self, payload):
    try:
      r = requests.get(self._url(), params = payload, headers = make_ua(self.mailto, self.ua_string))
      r.raise_for_status()
    except requests.exceptions.HTTPError:
      try:
        f = r.json()
        raise RequestError(r.status_code, f['message'][0]['message'])
      except:
        r.raise_for_status()
    except requests.exceptions.RequestException as e:
      print(e)
    check_json(r)
    return r.json()

:param keyc: [String] your API key

    See http://labs.crossref.org/openurl/ for more info on this Crossref API service.

    Usage::

        from habanero import counts
        counts.citation_count(doi = "10.1371/journal.pone.0042793")
        counts.citation_count(doi = "10.1016/j.fbr.2012.01.001")
        # DOI not found
        ## FIXME
        counts.citation_count(doi = "10.1016/j.fbr.2012")
    '''
    args = {"id": "doi:" + doi, "pid": key, "noredirect": True}
    args = dict((k, v) for k, v in args.items() if v)
    res = requests.get(url, params = args, headers = make_ua(), **kwargs)
    xmldoc = minidom.parseString(res.content)
    val = xmldoc.getElementsByTagName('query')[0].attributes['fl_count'].value
    return int(str(val))