Part 1 & 2

Buckets.Logic/Rainbarrel.cs

@@ -0,0 +1,15 @@
+namespace Buckets.Logic
+{
+    public class Rainbarrel : Container
+    {
+        private readonly int[] ALLOWED_CAPACITIES = [80, 100, 120];
+
+        public Rainbarrel(int capacity, int content) : base(capacity, content)
+        {
+            if (!ALLOWED_CAPACITIES.Contains(capacity))
+            {
+                throw new ArgumentException($"Capacity must be one of the following values: {string.Join(", ", ALLOWED_CAPACITIES)}.");
+            }
+        }
+    }
+}