original_string: protected function _storeHeader($headerName, $value, $append = false)
      {
          if (isset($this->_headers[$headerName])) {
              $this->_headers[$headerName][] = $value;
          } else {
              $this->_headers[$headerName] = array($value);
          }
  
          if ($append) {
              $this->_headers[$headerName]['append'] = true;
          }
  
      }
code: protected function _storeHeader($headerName, $value, $append = false)
      {
          if (isset($this->_headers[$headerName])) {
              $this->_headers[$headerName][] = $value;
          } else {
              $this->_headers[$headerName] = array($value);
          }
  
          if ($append) {
              $this->_headers[$headerName]['append'] = true;
          }
  
      }
code_tokens: protected function _storeHeader ( $ headerName , $ value , $ append = false ) { if ( isset ( $ this -> _headers [ $ headerName ] ) ) { $ this -> _headers [ $ headerName ] [ ] = $ value ; } else { $ this -> _headers [ $ headerName ] = array ( $ value ) ; } if ( $ append ) { $ this -> _headers [ $ headerName ] [ 'append' ] = true ; } }
docstring: Add a header to the message
  
  Adds a header to this message. If append is true and the header already
  exists, raises a flag indicating that the header should be appended.
  
  @param string  $headerName
  @param string  $value
  @param bool $append
docstring_tokens: Add a header to the message