def filters(type=nil)
      unless(type)
        @filters.dup
      else
        const = Splib.find_const(type)
        type = const unless const.nil?
        @filters[type] ? @filters[type].dup : nil
      end
    end
def filters(type=nil)
      unless(type)
        @filters.dup
      else
        const = Splib.find_const(type)
        type = const unless const.nil?
        @filters[type] ? @filters[type].dup : nil
      end
    end
type:: Object types
 Return filters of given type or all filters
 if not type is supplied