# File lib/hiera/backend.rb, line 47
      def datasources(scope, override=nil, hierarchy=nil)
        if hierarchy
          hierarchy = [hierarchy]
        elsif Config.include?(:hierarchy)
          hierarchy = [Config[:hierarchy]].flatten
        else
          hierarchy = ["common"]
        end

        hierarchy.insert(0, override) if override

        hierarchy.flatten.map do |source|
          source = parse_string(source, scope)
          yield(source) unless source == "" or source =~ /(^\/|\/\/|\/$)/
        end
      end