docs: def authorized_request(self, method, url, **kwargs):
          """Shortcut for requests.request with proper Authorization header.
  
          Note:
              If you put auth keyword argument or Authorization in headers
              keyword argument, this will raise an exception.
              Decide what you want to do!
  
          Args:
              method (str) - HTTP method of this request, like GET or POST.
              url (str) - URL of this request (one of Google APIs).
  
          Examples:
              >>> scope = 'https://www.googleapis.com/auth/plus.login'
              >>> url = 'https://www.googleapis.com/plus/v1/people' \
              >>>         '?query=Guuido+van+Rossum'
              >>> key = json.load(open('/path/to/credentials.json'))
              >>> auth = ServiceAccount.from_json(key=key, scopes=scope)
              >>> auth.authorized_request(method='get', url=url)
  
          Returns:
              requests.Response
          """
          headers = kwargs.pop('headers', {})
          if headers.get('Authorization') or kwargs.get('auth'):
              raise ValueError("Found custom Authorization header, "
                               "method call would override it.")
          headers['Authorization'] = 'Bearer ' + self.access_token
  
          return requests.request(method, url, headers=headers, **kwargs)