# File lib/rotp/totp.rb, line 39
    def verify(otp, drift_ahead: 0, drift_behind: 0, after: nil, at: Time.now)
      timecodes = get_timecodes(at, drift_behind, drift_ahead)

      timecodes = timecodes.select { |t| t > timecode(after) } if after

      result = nil
      timecodes.each do |t|
        result = t * interval if super(otp, generate_otp(t))
      end
      result
    end