code: def perform
        if can_perform?
          response = HTTPI.post(uri, params_string)
          responder.from_json(response.body)
        else
          fail Bitkassa::Exception,
               "Your merchant_id or merchant_key are not set"
        end
      end
docs: Initalize a request
   * +attributes+ +Hash+
  
   Make the request.
  
   returns +Bitkassa::PaymentResponse+ Regardless of the response, this
   this PaymentResponse is initialized.
  
   When a payment cannot be made because of incorrect or missing data,
   a +Bitkassa::Exception+ is raised.