Convert bytes to base58

bytes-to-base58

#!/usr/bin/env python3

import sys

base58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"

def base_encode(octets, alphabet):
    base = len(alphabet)
    bignum = 0
    for (index, octet) in enumerate(reversed(octets)):
        bignum += octet * (256 ** index)

    output = []
    while bignum >= base:
        bignum, mod = divmod(bignum, base)
        output.append(alphabet[mod])
    output.append(alphabet[bignum])

    return "".join(reversed(output))

def main():
    octets = sys.stdin.buffer.read(1048577)
    if len(octets) > 1048576:
        sys.stderr.write("Sorry, only input of up to 1 MB is supported")
        sys.exit(1)
    print(base_encode(octets, base58))

if __name__ == "__main__":
    main()

Hi. I'm new in the Phyton Programming Language. I was wndering how to run a .py file in my laptop. Hope you could help. Mine's OS is Windows 7 ULtimate. Thanks