# File lib/aws/simple_db/item_collection.rb, line 632
      def coerce_substitution(subst)
        if subst.kind_of?(Array)
          "(" +
            subst.flatten.map { |s| coerce_substitution(s) }.join(", ") + ")"
        else
          "'" + subst.to_s.gsub("'", "''") + "'"
        end
      end