diff --git a/ConfigParser.cs b/ConfigParser.cs
index 272c9e90875f498a5bb1234b1d766d597d070cab..5227b2f78ceeb5ec6e5778ba4bf0019c624ddca1 100644
--- a/ConfigParser.cs
+++ b/ConfigParser.cs
@@ -333,6 +333,10 @@ class ConfigSection: IReadOnlyList<ConfigValue>
 			throw new ConfigNotDefinedException(this, key);
 		return r;
 	}
+	public bool Contains(string key)
+	{
+		return valueByName.ContainsKey(key);
+	}
 	public void Print(TextWriter w)
 	{
 		w.WriteLine($"### {SectionName}");