1 files changed, 4 insertions, 4 deletions
diff --git a/ext/tk/lib/multi-tk.rb b/ext/tk/lib/multi-tk.rb
index 6d048e91bc..e8bbf67de1 100644
--- a/ext/tk/lib/multi-tk.rb
+++ b/ext/tk/lib/multi-tk.rb
@@ -1730,11 +1730,11 @@ class << MultiTkIp
     __getip._invoke_with_enc(*args)
   end
 
-  def _toUTF8(str, encoding)
+  def _toUTF8(str, encoding=nil)
     __getip._toUTF8(str, encoding)
   end
 
-  def _fromUTF8(str, encoding)
+  def _fromUTF8(str, encoding=nil)
     __getip._fromUTF8(str, encoding)
   end
 
@@ -2119,11 +2119,11 @@ class MultiTkIp
     @interp._invoke_with_enc(*args)
   end
 
-  def _toUTF8(str, encoding)
+  def _toUTF8(str, encoding=nil)
     @interp._toUTF8(str, encoding)
   end
 
-  def _fromUTF8(str, encoding)
+  def _fromUTF8(str, encoding=nil)
     @interp._fromUTF8(str, encoding)
   end