code: def initiate(self, callback=None):
          
          return initiate(self.mw_uri, self.consumer_token,
                          callback=callback or self.callback,
                          user_agent=self.user_agent)
docs: Initiate an OAuth handshake with MediaWiki.
  
          :Parameters:
              callback : `str`
                  Callback URL. Defaults to 'oob'.
  
          :Returns:
              A `tuple` of two values:
  
              * a MediaWiki URL to direct the user to
              * a :class:`~mwoauth.RequestToken` representing an access request