code: def token_of_request(self, url, body=None, content_type=None):
          
          parsed_url = urlparse(url)
          query = parsed_url.query
          path = parsed_url.path
          data = path
          if query != '':
              data = ''.join([data, '?', query])
          data = ''.join([data, "\n"])
  
          if body:
              mimes = [
                  'application/x-www-form-urlencoded'
              ]
              if content_type in mimes:
                  data += body
  
          return '{0}:{1}'.format(self.__access_key, self.__token(data))
docs: 带请求体的签名（本质上是管理凭证的签名）
  
          Args:
              url:          待签名请求的url
              body:         待签名请求的body
              content_type: 待签名请求的body的Content-Type
  
          Returns:
              管理凭证