# File lib/thinking_sphinx/active_record.rb, line 241
      def source_of_sphinx_index
        define_indexes
        possible_models = self.sphinx_indexes.collect { |index| index.model }
        return self if possible_models.include?(self)

        parent = self.superclass
        while !possible_models.include?(parent) && parent != ::ActiveRecord::Base
          parent = parent.superclass
        end

        return parent
      end