diff --git a/curses.gemspec b/curses.gemspec
index 0549113b..897bf89e 100644
--- a/curses.gemspec
+++ b/curses.gemspec
@@ -9,7 +9,7 @@ Gem::Specification.new { |s|
   s.files = `git ls-files --recurse-submodules -z`.split("\x0")
   s.extensions = ["ext/curses/extconf.rb"]
   s.require_path = "lib"
-  s.required_ruby_version = Gem::Requirement.new('>= 2.6.0')
+  s.required_ruby_version = Gem::Requirement.new('>= 3.0')
   s.licenses = ['Ruby', 'BSD-2-Clause']
   s.add_development_dependency 'bundler'
   s.add_development_dependency 'rake'
diff --git a/lib/curses.rb b/lib/curses.rb
index c7097c5c..1109f101 100644
--- a/lib/curses.rb
+++ b/lib/curses.rb
@@ -87,3 +87,10 @@ def prev_match
   end
 end
 
+module Curses
+  module_function
+
+  def chgat(...)
+    Curses.stdscr.chgat(...)
+  end
+end
diff --git a/sample/attr_demo.rb b/sample/attr_demo.rb
index 8c90704e..b2af2e7e 100644
--- a/sample/attr_demo.rb
+++ b/sample/attr_demo.rb
@@ -27,8 +27,8 @@
   }
   getch
   setpos(0, 0)
-  Curses.stdscr.chgat(6, A_UNDERLINE)
+  chgat(6, A_UNDERLINE)
   getch
 ensure
   close_screen
-end
\ No newline at end of file
+end