# File ../src/optiflag.rb, line 391
    def optional_flag(flag_name_pair,hash={},&the_block)
      flag(flag_name_pair,hash,&the_block)
      flag_name_pair = [flag_name_pair] if flag_name_pair.class == String
      name = flag_name_pair[1] || flag_name_pair[0]
      flag_properties name.to_sym do
        optional
      end
    end