Time-based One-time Password algorithm in python python3

TOTP.py

import datetime
import time
import hashlib
import hmac
import base64

class OTP(object):
	digits=6
	digest=hashlib.sha1
	def __init__(self,s: str) -> None:
		self.secret = s

	@staticmethod
	def int_to_bytestring(i: int, padding: int = 8) -> bytes:
		result = bytearray()
		while i != 0:
			result.append(i & 0xFF)
			i >>= 8
		return bytes(bytearray(reversed(result)).rjust(padding, b'\0'))

	def byte_secret(self) -> bytes:
		missing_padding = len(self.secret) % 8
		if missing_padding != 0:
			self.secret += '=' * (8 - missing_padding)
		return base64.b32decode(self.secret, casefold=True)

	def generate_otp(self, input: int) -> str:
		hasher = hmac.new(self.byte_secret(), self.int_to_bytestring(input), self.digest)
		hmac_hash = bytearray(hasher.digest())
		offset = hmac_hash[-1] & 0xf
		code = ((hmac_hash[offset] & 0x7f) << 24 |
				(hmac_hash[offset + 1] & 0xff) << 16 |
				(hmac_hash[offset + 2] & 0xff) << 8 |
				(hmac_hash[offset + 3] & 0xff))
		str_code = str(code % 10 ** self.digits)
		while len(str_code) < self.digits:
			str_code = '0' + str_code
		return str_code[0:3]+"-"+str_code[3:6]  

	def Now(self) -> str:
		return self.generate_otp(int(time.time()/30))

if __name__ == "__main__":
	print(OTP("KEY HERE").Now())