exercicio 'leap' no percurso Dart concluido

dart/leap/lib/leap.dart

@@ -0,0 +1,5 @@
+class Leap {
+  bool leapYear(int year) {
+    return ((year % 4) == 0 && ((year % 400 == 0) || (year % 100 != 0)));
+  }
+}