code: def _pre_request(self, url, method = u"get", data = None, headers=None, **kwargs):
          
          header = {
              u"Content-Type": u"application/json",
              u"User-Agent": u"salesking_api_py_v1",
          }
          if headers:
              headers.update(header)
          else:
              headers = header
          if url.find(self.base_url) !=0:
              url = u"%s%s" %(self.base_url, url)
          return (url, method, data, headers, kwargs)
docs: hook for manipulating the _pre request data