code: def find_application(app_id=None, app_name=None):
          
          LOGGER.debug("ApplicationService.find_application")
          if (app_id is None or not app_id) and (app_name is None or not app_name):
              raise exceptions.ArianeCallParametersError('id and name')
  
          if (app_id is not None and app_id) and (app_name is not None and app_name):
              LOGGER.warn('ApplicationService.find_application - Both id and name are defined. '
                          'Will give you search on id.')
              app_name = None
  
          params = None
          if app_id is not None and app_id:
              params = {'id': app_id}
          elif app_name is not None and app_name:
              params = {'name': app_name}
  
          ret = None
          if params is not None:
              args = {'http_operation': 'GET', 'operation_path': 'get', 'parameters': params}
              response = ApplicationService.requester.call(args)
              if response.rc == 0:
                  ret = Application.json_2_application(response.response_content)
              elif response.rc != 404:
                  err_msg = 'ApplicationService.find_application - Problem while finding application (id:' + \
                            str(app_id) + ', name:' + str(app_name) + '). ' + \
                            'Reason: ' + str(response.response_content) + '-' + str(response.error_message) + \
                            " (" + str(response.rc) + ")"
                  LOGGER.warning(
                      err_msg
                  )
  
          return ret
docs: find the application according application id (prioritary) or application name
          :param app_id: the application id
          :param app_name: the application name
          :return: found application or None if not found