code: func (e *helperMethodContent) WriteTo(w io.Writer) (int64, error) {
  	var bf bytes.Buffer
  
  	inner := e.src.inner
  	if inner == nil {
  		return 0, fmt.Errorf("inner is not specified [file: %s][line: %d]", e.ln.fileName(), e.ln.no)
  	}
  
  	// Write a define action.
  	bf.WriteString(fmt.Sprintf(actionDefine, e.opts.DelimLeft, inner.path+doubleColon+e.name, e.opts.DelimRight))
  
  	// Write the children's HTML.
  	if i, err := e.writeChildren(&bf); err != nil {
  		return i, err
  	}
  
  	// Write an end action.
  	bf.WriteString(fmt.Sprintf(actionEnd, e.opts.DelimLeft, e.opts.DelimRight))
  
  	// Write the buffer.
  	i, err := w.Write(bf.Bytes())
  
  	return int64(i), err
  }
docs: // WriteTo writes data to w.