Write the function is_alpha_num(s) that takes in a string and returns True if there is at least one character and every character in the string is a letter or a digit. The function returns False otherwise.Your function should call the is_alpha and is_digit functions that you have already written. Write the function is_alpha_num(s) that takes in a string and returns True if there is at least one character and every character in the string is a letter or a digit. The function returns False otherwise.Your function should call the is_alpha and is_digit functions that you have already written.