def swap_case(s):
    a=""
    for i in range(len(s)):
        if s[i].islower():
            a=a+s[i].upper()
        else:
            a=a+s[i].lower()
    return a


97966cf864621f0c4b8ce01cefd04f94a7a6bc39
<mask token>

def swap_case(s):
    a = ''
    for i in range(len(s)):
        if s[i].islower():
            a = a + s[i].upper()
        else:
            a = a + s[i].lower()
    return a

def swap_case(s):
    a=""
    for i in range(len(s)):
        if s[i].islower():
            a=a+s[i].upper()
        else:
            a=a+s[i].lower()
    return a

