Change the case of a string

strings_03_case.py

def to_uppercase(input_string:str) -> str:
    return input_string.upper()

def to_lowercase(input_string:str) -> str:
    return input_string.lower()

def to_sentencecase(input_string:str) -> str:
    return input_string.capitalize()

def to_titlecase(input_string:str) -> str:
    return input_string.title()

def to_swapcase(input_string:str) -> str:
    return input_string.swapcase()

assert to_uppercase("the end of time") == "THE END OF TIME"
assert to_lowercase("The End Of Time") == "the end of time"
assert to_sentencecase("The End of Time") == "The end of time"
assert to_titlecase("the end of time") == "The End Of Time"
assert to_swapcase("The End Of Time") == "tHE eND oF tIME"