code: public function validate(string $sValue = null) : bool
      {
          if ($this->_sType == 'DateTime') {
              
              if (preg_match('#^[0-9]{4}/[0-9]{2}/[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}#', $sValue)) {
                  
                  return true;
              }
          }
          
          return false;
      }
docs: validate the Type
  
  @access public
  @param  string $sValue
  @return bool