diff --git a/bin/example.rb b/bin/example.rb
index 2575dc7..d1b8fbc 100755
--- a/bin/example.rb
+++ b/bin/example.rb
@@ -3,6 +3,7 @@
 require 'pathname'
 require 'shellwords'
 require 'stringio'
+require 'ipaddr'
 require_relative '../lib/dencli'
 
 cli = DenCli.new :example, "This is an example for generate a DenCli-API"
diff --git a/lib/dencli/cmd.rb b/lib/dencli/cmd.rb
index e16385d..0d214f5 100644
--- a/lib/dencli/cmd.rb
+++ b/lib/dencli/cmd.rb
@@ -217,8 +217,8 @@ class DenCli::CMD
 		end
 	end
 
-	def opt name, opt, *args, desc, &conv
-		r = Opt.new( self, name, opt, *args, desc, &conv)
+	def opt name, opt, *args, desc, default: NilClass, &conv
+		r = Opt.new( self, name, opt, *args, desc, default: default, &conv)
 		@options[r.name] = r
 		self
 	end