class ActiveSupport::Duration

def inspect #:nodoc:
  parts.
    reduce(::Hash.new(0)) { |h,(l,r)| h[l] += r; h }.
    sort_by {|unit,  _ | [:years, :months, :days, :minutes, :seconds].index(unit)}.
    map     {|unit, val| "#{val} #{val == 1 ? unit.to_s.chop : unit.to_s}"}.
    to_sentence(locale: ::I18n.default_locale)
end