This error is coming because the interpreter is replacing the %d with i and then trying to add 1 to a str, ie, adding a str and an int. In order to correct this, just surround the i+1 in parentheses. exampleprint("\ Num %d" % (i+1))

You need to indent all the method definitions so that they are under the class. exampleclass A(): def __init__(): passYou can learn more about indentation and how it needs to be used in Python here −https://www.tutorialspoint.com/python_online_training/python_lines_and_indentation.asp