def include?(timestamp)
      return false if earlier?(timestamp) || later?(timestamp)

      recurrence = finite? ? self : starts(timestamp)

      recurrence.events.lazy.each do |event|
        return true if event == timestamp
        return false if event > timestamp
      end or false
    end
def include?(timestamp)
      return false if earlier?(timestamp) || later?(timestamp)

      recurrence = finite? ? self : starts(timestamp)

      recurrence.events.lazy.each do |event|
        return true if event == timestamp
        return false if event > timestamp
      end or false
    end
Return true/false if given timestamp equals a timestamp given
 by the recurrence

 @return [Boolean] whether or not timestamp is included in recurrence