original_string: public function add($key, $value)
      {
          $header = $this->get($key, true);
          if (is_array($value)) {
              $header = array_merge($header, $value);
          } else {
              $header[] = $value;
          }
          parent::set($this->normalizeKey($key), $header);
      }
code: public function add($key, $value)
      {
          $header = $this->get($key, true);
          if (is_array($value)) {
              $header = array_merge($header, $value);
          } else {
              $header[] = $value;
          }
          parent::set($this->normalizeKey($key), $header);
      }
code_tokens: public function add ( $ key , $ value ) { $ header = $ this -> get ( $ key , true ) ; if ( is_array ( $ value ) ) { $ header = array_merge ( $ header , $ value ) ; } else { $ header [ ] = $ value ; } parent :: set ( $ this -> normalizeKey ( $ key ) , $ header ) ; }
docstring: Add data to key
  
  @param string $key   The data key
  @param mixed  $value The data value
  @api
docstring_tokens: Add data to key