new

# File activesupport/lib/active_support/duration.rb, line 223
    def initialize(value, parts, variable = nil) # :nodoc:
      @value, @parts = value, parts
      @parts.reject! { |k, v| v.zero? } unless value == 0
      @parts.freeze
      @variable = variable

      if @variable.nil?
        @variable = @parts.any? { |part, _| VARIABLE_PARTS.include?(part) }
      end
    end