def last_updated(sheet)
from = sheet.updated_at.to_i
to = Time.now.to_i
from = from.to_time if from.respond_to?(:to_time)
to = to.to_time if to.respond_to?(:to_time)
distance = (((to - from).abs)/60).round
case distance
when 0..1 then return (distance==0) ? 'less than a minute' : '1 minute'
when 2..45 then "#{distance} minutes"
when 46..90 then 'about 1 hour'
when 90..1440 then "about #{(distance.to_f / 60.0).round} hours"
when 1441..2880 then '1 day'
else "#{(distance / 1440).round} days"
end
end