original_string: protected function helper($helperName)
      {
          if (!isset($this->helpers[$helperName])) {
              throw new \InvalidArgumentException('Unable to locate controller helper: ' . $helperName);
          }
  
          return $this->helpers[$helperName];
      }
code: protected function helper($helperName)
      {
          if (!isset($this->helpers[$helperName])) {
              throw new \InvalidArgumentException('Unable to locate controller helper: ' . $helperName);
          }
  
          return $this->helpers[$helperName];
      }
code_tokens: protected function helper ( $ helperName ) { if ( ! isset ( $ this -> helpers [ $ helperName ] ) ) { throw new \ InvalidArgumentException ( 'Unable to locate controller helper: ' . $ helperName ) ; } return $ this -> helpers [ $ helperName ] ; }
docstring: Obtain a controller helper by its key name.
  
  @param string $helperName
  
  @throws \InvalidArgumentException
  
  @return mixed
docstring_tokens: Obtain a controller helper by its key name .