wizpert.py

def main():
    StNumber, StMark = input('Enter student number and student mark separated by a comma')
    StNumber = StNumber.upper()
    if len(StNumber)==9 and StNumber[0:6].isalpha() and StNumber[6:].isdigit():
        with open("output.txt", "w") as f:
            f.write(StNumber + "," + StMark + "\n")
    else:
        print("Invalid student number")