Python revertir casos de mayúsculas y minúsculas

swap_case_upper_lower.py

def swap_case(text: str):
    swap = ""
    for word in text:
        if word.isupper():
            swap += word.lower()
            continue
        
        if word.islower():
            swap += word.upper()
            continue
        
        swap += word    
            
    return swap

text = "HeLLo. H"
print(swap_case(text))