feat: Added a dictionary extension method for getting or adding a new value via func

ICD.Common.Utils/Extensions/DictionaryExtensions.cs

@@ -147,14 +147,38 @@ namespace ICD.Common.Utils.Extensions
 			if (extends == null)
 				throw new ArgumentNullException("extends");
 
-			// ReSharper disable once CompareNonConstrainedGenericWithNull
+// ReSharper disable CompareNonConstrainedGenericWithNull
 			if (key == null)
+// ReSharper restore CompareNonConstrainedGenericWithNull
+				throw new ArgumentNullException("key");
+
+			return extends.GetOrAddNew(key, () => ReflectionUtils.CreateInstance<TValue>());
+		}
+
+		/// <summary>
+		/// If the key is present in the dictionary return the value, otherwise add a new value to the dictionary and return it.
+		/// </summary>
+		/// <typeparam name="TKey"></typeparam>
+		/// <typeparam name="TValue"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="key"></param>
+		/// <param name="valueFunc"></param>
+		/// <returns></returns>
+		[PublicAPI]
+		public static TValue GetOrAddNew<TKey, TValue>(this IDictionary<TKey, TValue> extends, TKey key, Func<TValue> valueFunc)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+// ReSharper disable CompareNonConstrainedGenericWithNull
+			if (key == null)
+// ReSharper restore CompareNonConstrainedGenericWithNull
 				throw new ArgumentNullException("key");
 
 			TValue value;
 			if (!extends.TryGetValue(key, out value))
 			{
-				value = ReflectionUtils.CreateInstance<TValue>();
+				value = valueFunc();
 				extends.Add(key, value);
 			}