Pokemon hex data to binary converter

#!/bin/python
# coding: utf-8
# datconv.py

import sys, re, argparse

def str2byt(x):
    done = False
    out = b''
    byte = 0
    for nybble in x:
        if not done:
            byte = int( nybble, 16 )
            byte <<= 4
        else:
            byte |= ( int( nybble, 16 ) & 0xF )
            out = out + bytes([byte])
        done = not done
    return out

hx1 = lambda n: hex(n)[2:].zfill(2)

REGEX_DEC = re.compile(r'^  d[bw]   ((?:[0-9]{3},?)+)\s*(?:;.*)?$')
REGEX_HEX = re.compile(r'^  d[bw]   ((?:0(?:[A-Fa-f0-9]{2})+h,?)+)\s*(?:;.*)?$')

def divhx(x):
    pcs = []
    for i in range(len(x) // 2):
        pcs.append(x[i*2:i*2+2])
    return ''.join(pcs[::-1])

def divhxl(x):
    out = ''
    for k in x:
        out += divhx(k)
    return out

def Main(args):
    txt = open(args.filein, 'r').read()
    v = not args.quiet
    lins = txt.split('\n')
    if args.guess:
        r1 = REGEX_DEC
        r2 = REGEX_HEX
        for i in range(len(lins)):
            if r1.match(lins[i]):
                args.decimal = True
                break
            elif r2.match(lins[i]):
                args.decimal = False
                break
        else:
            raise Exception
    if args.decimal:
        reg = REGEX_DEC
    else:
        reg = REGEX_HEX
    datout = ''
    uuct = 0
    for i,l in enumerate(lins):
        mm = reg.match(l)
        if mm:
            cur_dats = mm.groups()[0].split(',')
            if args.decimal:
                cur_dats_2 = [hx1(int(x[1:-1])) for x in cur_dats]
            else:
                cur_dats_2 = [x[1:-1] for x in cur_dats]
            datout += ''.join(cur_dats_2)
        else:
            if v:
                print('Line does not match pattern:')
                print(i+1, l)
                uuct += 1
                if uuct > 10:
                    input()
                    uuct = 0

    open(args.fileout, 'wb').write(str2byt(datout))

if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='converts pokesource data to bin')
    parser.add_argument('filein', type=str, help='file in')
    parser.add_argument('fileout', type=str, help='file out')
    parser.add_argument('-q', dest='quiet', action='store_true', help='quiet')
    parser.add_argument('-d', dest='decimal', action='store_true', help='data is decimal')
    parser.add_argument('-g', dest='guess', action='store_true', help='guess hex or dec')

    args = parser.parse_args()

    Main(args)
#