code: private function getProperty(string $property, $locale = null)
      {
          $localeCode = $this->getLocaleFromInput($locale);
  
          // This checks happens after the call to getLocaleFromInput
          // to make sure the Exception for invalid locales is still thrown.
          if (null === $this->$property) {
              return null;
          }
  
          $localeCode = $this->walkFallbackChain($this->$property, $localeCode, $this->sys->getEnvironment());
  
          return null === $localeCode
              ? null
              : $this->{$property}[$localeCode];
      }
docs: @param string             $property
  @param Locale|string|null $locale
  
  @throws \InvalidArgumentException when $locale is not one of the locales supported by the space
  
  @return string|FileInterface|null