class ActiveSupport::Duration

def ago(time = ::Time.current)

Experimental RBS support (using type sampling data from the type_fusion project). 

def ago: (?ActiveSupport::TimeWithZone time) -> ActiveSupport::TimeWithZone

This signature was generated using 1 sample from 1 application.

as this Duration represents.
Calculates a new Time or Date that is as far in the past 
def ago(time = ::Time.current)
  sum(-1, time)
end