# File lib/gdata/client/base.rb, line 146
      def clientlogin(username, password, captcha_token = nil, captcha_answer = nil, service = nil)
        if service.nil?
          service = @clientlogin_service
        end
        @auth_handler = GData::Auth::ClientLogin.new(service)
        if @clientlogin_url
          @auth_handler.auth_url = @clientlogin_url
        end
        source = GData::Auth::SOURCE_LIB_STRING + @source
        @auth_handler.get_token(username, password, source, captcha_token, captcha_answer)
      end