void main() {
List<Map<String, dynamic>> users = [
  { 'name': "Gaspard", 'age': 18,'nationality' :"French"},
  { 'name': "Louise", 'age': 21 ,'nationality' :"French"},
  { 'name': "Giulia", 'age': 23,'nationality' :"Italian"},
   { 'name': "Friederike", 'age': 23,'nationality' :"German"},
];
var over18s = users.where((user) {
  return user['age'] > 18;
});
print("Over 18 condition:\n $over18s");

var noOpFilter = users.where((user) {
  return true;
});

print("No operation filter:\n $noOpFilter");

  var isFrench = users.where((user) {
  return user['nationality'] == "French";
});
print("French condition:\n $isFrench");

var isFrenchOrItalian = users.where((user) {
  return user['nationality'] == "French" || user['nationality'] == "Italian";
});
print("French or Italian Condition:\n $isFrenchOrItalian");
}