# File lib/dm-types/comma_separated_list.rb, line 12
      def self.dump(value, property)
        if value.nil?
          nil
        elsif value.kind_of?(Array)
          super(value, property)
        elsif value.kind_of?(String)
          v = (value || "").split(",").
            compact.
            map { |i| i.downcase.strip }.
            reject { |i| i.blank? }.
            uniq
          super(v, property)
        else
          raise ArgumentError, "+value+ of CommaSeparatedList must be a string, an array or nil, but given #{value.inspect}"
        end
      end