repeater.py

import sys


def main(text):
    n, s, result = '', '', []
    for i in text:
        if i.isdigit():
            n += i
        else:
            if n:
                result.append(s * int(n))
            s = i
            n = ''
    result.append(s * int(n))
    return ''.join(result)



if __name__ == '__main__':
    print(main(sys.argv[1]))

python repeater.py a1b2c3d4e5