# File lib/dm-core/associations/relationship.rb, line 221
      def parent_model
        return @parent_model if defined?(@parent_model)
        parent_model_name = self.parent_model_name
        @parent_model = (@child_model || Object).find_const(parent_model_name)
      rescue NameError
        raise NameError, "Cannot find the parent_model #{parent_model_name} for #{child_model_name} in #{name}"
      end