code: public function model2LangKey($modelName)
      {
          if (!is_string($modelName)) {
              $modelDisplay = is_object($modelName) ? get_class($modelName) : gettype($modelName);
              throw new \UnexpectedValueException("modelName has to be string not $modelDisplay");
          }
  
          if (isset($this->modelToLangName[$modelName])) {
              return $this->modelToLangName[$modelName];
          }
  
          $matches = [];
  
          if (preg_match('@\\\\([\w]+)$@', $modelName, $matches)) {
              $modelName = $matches[1];
          }
  
          return snake_case($modelName);
      }
docs: Returns the langClassName of $modelName
  
  @param string $modelName
  @return string