ago method

DateTime ago ({int days: 0, int hours: 0, int minutes: 0, int seconds: 0, int milliseconds: 0, int microseconds: 0 })

Returns the point in time that's given amount of time ago. The amount of time is the sum of individual parts. Parts are compatible with ones defined in Duration.

Implementation 

DateTime ago(
        {int days: 0,
        int hours: 0,
        int minutes: 0,
        int seconds: 0,
        int milliseconds: 0,
        int microseconds: 0}) =>
    agoBy(new Duration(
        days: days,
        hours: hours,
        minutes: minutes,
        seconds: seconds,
        milliseconds: milliseconds,
        microseconds: microseconds));