src/protocol/messages.js
function createExecuteSuccessResponseMessage(parentMessage, executionCount, metadata) {
  var content = {
    status: 'ok',
    execution_count: executionCount,
    payload: [],
    user_variables: {},
    user_expressions: {}
  };

  return newMessage(_messageNames.executeResponse, parentMessage, content, metadata);
}
function createExecuteSuccessResponseMessage(parentMessage, executionCount, metadata) {
  var content = {
    status: 'ok',
    execution_count: executionCount,
    payload: [],
    user_variables: {},
    user_expressions: {}
  };

  return newMessage(_messageNames.executeResponse, parentMessage, content, metadata);
}
Creates a success execution reply message.