code: def _req_files_add(self, pid, cname):
          
          url = self.web_api_url + '/add'
          data = locals()
          del data['self']
          req = Request(method='POST', url=url, data=data)
          res = self.http.send(req)
          if res.state:
              return res.content
          else:
              raise RequestFailure('Failed to access files API.')
docs: Add a directory
          :param str pid: parent directory id
          :param str cname: directory name