def find_workflow(workflow_name, custom_id)
      params = { ATTR_ID => custom_id, ATTR_NAME => workflow_name }
      params[ATTR_PROG] = PROG
      data = @http.get(instance_website_url(params))['data']
      data && @properties.object_from(
        data['name'],
        @serializer.decode(data['properties'])
      )
    rescue Zenaton::InternalError => exception
      return nil if exception.message =~ /No workflow instance found/
      raise exception
    end
def find_workflow(workflow_name, custom_id)
      params = { ATTR_ID => custom_id, ATTR_NAME => workflow_name }
      params[ATTR_PROG] = PROG
      data = @http.get(instance_website_url(params))['data']
      data && @properties.object_from(
        data['name'],
        @serializer.decode(data['properties'])
      )
    rescue Zenaton::InternalError => exception
      return nil if exception.message =~ /No workflow instance found/
      raise exception
    end
Finds a workflow
 @param workflow_name [String] the class name of the workflow
 @param custom_id [String] the custom ID of the workflow
 @return [Zenaton::Interfaces::Workflow, nil]