# Microsoft.Extensions.Configuration.Memory

``` diff
 namespace Microsoft.Extensions.Configuration.Memory {
-    public class MemoryConfigurationProvider : ConfigurationProvider, IEnumerable, IEnumerable<KeyValuePair<string, string>> {
+    public class MemoryConfigurationProvider : ConfigurationProvider, IEnumerable, IEnumerable<KeyValuePair<string, string?>> {
-        public void Add(string key, string value);
+        public void Add(string key, string? value);
-        public IEnumerator<KeyValuePair<string, string>> GetEnumerator();
+        public IEnumerator<KeyValuePair<string, string?>> GetEnumerator();
     }
     public class MemoryConfigurationSource : IConfigurationSource {
-        public IEnumerable<KeyValuePair<string, string>> InitialData { get; set; }
+        public IEnumerable<KeyValuePair<string, string?>>? InitialData { get; set; }
     }
 }
```

