diff --git a/lib/ipaddress/prefix.rb b/lib/ipaddress/prefix.rb
index 136f2d3457ca0cd77f369109ea76cd14a97c759d..e819800fbe5a6b3737868287ad0de57535bdd3ef 100644
--- a/lib/ipaddress/prefix.rb
+++ b/lib/ipaddress/prefix.rb
@@ -78,7 +78,7 @@ module IPAddress
       end
     end
     
-   end # class Prefix
+  end # class Prefix
 
 
   class Prefix32 < Prefix