diff --git a/lib/winrm/shells/base.rb b/lib/winrm/shells/base.rb
index 3d11ac49..ed8976a0 100644
--- a/lib/winrm/shells/base.rb
+++ b/lib/winrm/shells/base.rb
@@ -94,6 +94,10 @@ def close
         @shell_id = nil
       end
 
+      def self.finalize(connection_opts, transport, shell_id)
+        proc { Thread.new { close_shell(connection_opts, transport, shell_id) } }
+      end
+
       protected
 
       def send_command(_command, _arguments)
@@ -183,10 +187,6 @@ def add_finalizer
       def remove_finalizer
         ObjectSpace.undefine_finalizer(self)
       end
-
-      def self.finalize(connection_opts, transport, shell_id)
-        proc { Thread.new { close_shell(connection_opts, transport, shell_id) } }
-      end
     end
   end
 end