code: func (e *helperMethodYield) 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)
  	}
  
  	var templateExists bool
  
  	for _, innerE := range e.rslt.inner {
  		ln := innerE.Base().ln
  		if ln.isHelperMethodOf(helperMethodNameContent) && len(ln.tokens) > 2 && ln.tokens[2] == e.templateName {
  			templateExists = true
  			break
  		}
  	}
  
  	if templateExists {
  		bf.WriteString(fmt.Sprintf(actionTemplateWithPipeline, e.opts.DelimLeft, inner.path+doubleColon+e.templateName, dot, e.opts.DelimRight))
  	} else {
  		// Write the children's HTML.
  		if i, err := e.writeChildren(&bf); err != nil {
  			return i, err
  		}
  	}
  
  	i, err := w.Write(bf.Bytes())
  
  	return int64(i), err
  }
docs: // WriteTo writes data to w.