code: public function isResponsible($level, $message, $file = null, $line = null, array $context = [])
      {
          foreach ($this->errorHandlers as $errorHandler) {
              if ($errorHandler->isResponsible($level, $message, $file, $line, $context) == true) {
                  return true;
              }
          }
  
          return false;
      }
docs: checks whether this error handler is responsible for the given error
  
  This method is called in case the level is 0. It decides whether the
  error has to be handled or if it can be omitted.
  
  @param   int     $level    level of the raised error
  @param   string  $message  error message
  @param   string  $file     filename that the error was raised in
  @param   int     $line     line number the error was raised at
  @param   array   $context  array of every variable that existed in the scope the error was triggered in
  @return  bool    true if error handler is responsible, else false