def archived_date_str(obj=nil) 
      if obj 
        if d = obj.send( archived_time_attribute)
          return d.strftime('%Y-%m-%d')
        end
      else
        # assume acting on self
        return self.send(archived_time_attribute).strftime('%Y-%m-%d')
      end
    end
def archived_date_str(obj=nil) 
      if obj 
        if d = obj.send( archived_time_attribute)
          return d.strftime('%Y-%m-%d')
        end
      else
        # assume acting on self
        return self.send(archived_time_attribute).strftime('%Y-%m-%d')
      end
    end
a convenience method
 takes in an obj that has :rails_updated_at, either a EstoreConventional record
  or a Hashie::Mash

 returns a String in YYYY-MM-DD format
 awkward construction (acts on an object, rather than takes a message) is because
 hashie object may be involved...