diff --git a/lib/train/transports/ssh_connection.rb b/lib/train/transports/ssh_connection.rb
index 65e150c1..5e07194c 100644
--- a/lib/train/transports/ssh_connection.rb
+++ b/lib/train/transports/ssh_connection.rb
@@ -217,7 +217,7 @@ def session(retry_options = {})
     # @api private
     def to_s
       options_to_print = @options.clone
-      options_to_print[:password] = "<hidden>" if options_to_print.has_key?(:password)
+      options_to_print[:password] = '<hidden>' if options_to_print.key?(:password)
       "#{@username}@#{@hostname}<#{options_to_print.inspect}>"
     end