function getPropertyDetails() {
  var add = '0x63dC7B47BF9F0c257aE1a17B781f43c1d4DF2a53';
  Rental.getProperityCount(add,function() {
    Rental.getProperityCount((error, result) => {
      if (!error)
        alert(" property count: " + result);
      else
        alert("ERROR!");
    });
});
}