Cave of Python

You can associate a message with an exception when you raise it. Builtin exceptions often have messages associated with them already.

To get the message when you catch the exception, just give it a name with the as keyword.

def raise_exception():
    text = input("Enter 'error' to raise an exception: ")

    if text == "error":
        raise Exception("Oh no, an exception!")
    
def main():

    try:
        raise_exception()
    except Exception as e:
        print(e)

main()

Enter 'error' to raise an exception: error
Oh no, an exception!Enter 'error' to raise an exception: error
Oh no, an exception!