def format_value
      case @type
      when "string"
        @value
      when "date"
        @value.kind_of?(Time) ? @value.iso8601(3) : @value
      when "int"
        @value.kind_of?(Integer) ? @value : @value.to_i
      when "float"
        @value.kind_of?(Float) ? @value : @value.to_f
      when "boolean"
        @value
      when "id"
        @value
      end.to_s
    end
def format_value
      case @type
      when "string"
        @value
      when "date"
        @value.kind_of?(Time) ? @value.iso8601(3) : @value
      when "int"
        @value.kind_of?(Integer) ? @value : @value.to_i
      when "float"
        @value.kind_of?(Float) ? @value : @value.to_f
      when "boolean"
        @value
      when "id"
        @value
      end.to_s
    end
Format the value.

 @return [String]