# File app/models/timeslot.rb, line 161
  def interval_to_seconds(time)
    # A nil is a nil is a nil. And if the interval includes a ':',
    # Postgres will grok it better than me.
    return time if time.nil? or time=~/:/
    seconds = time.to_i
    if seconds >= 2**31 or seconds <= -2**31
      raise TypeError, "#{time} interval out of range" 
    end
    "#{seconds} seconds"
  end