# File lib/thor/util.rb, line 58
      def namespaces_in_content(contents, file = __FILE__)
        old_constants = Thor::Base.subclasses.dup
        Thor::Base.subclasses.clear

        load_thorfile(file, contents)

        new_constants = Thor::Base.subclasses.dup
        Thor::Base.subclasses.replace(old_constants)

        new_constants.map!(&:namespace)
        new_constants.compact!
        new_constants
      end