diff --git a/lib/uplot/command/params.rb b/lib/uplot/command/params.rb
index 2633d8d..b385161 100644
--- a/lib/uplot/command/params.rb
+++ b/lib/uplot/command/params.rb
@@ -5,7 +5,7 @@ module Uplot
     # UnicodePlot parameters.
     # * Normally in a Ruby program, you might use hash for the parameter object.
     # * Here, I use Struct for 2 safety reason.
-    # * The keys are static in Struct. 
+    # * The keys are static in Struct.
     # * Struct does not conflict with keyword arguments. Hash dose.
     Params = Struct.new(
       # Sort me!