Why this error came in my program when I use casefold and swapcase

Question

str='pivyash'
capitalize converts first character of string to capital
x=capitalize(str)
print(x)
x=casefold(str)
print (x)

Answer 1

str.capitalize()
str.casefold()

And yes it took me two minutes to Google and check the right way of using them

Answer 2

I think you against me very excellent keep rocking 👌🏻