example.py

def is_unique1(str):
    str_set = set()
    for char in str:
       str_set.add(char.lower())

    if(len(str_set) == len(str)):
        return True
    else: 
        return False

print(is_unique1("Aqwea")) # False
print(is_unique1("Aaqwe")) # False
print(is_unique1("abc")) # True


def is_unique2(str):
    i = 0

    for i in range(i,len(str)-1):
        j = i+1
        for j in range(j,len(str)):
            if(str[i].lower() == str[j].lower()):
                return False
       
    return True
   
print(is_unique2("Aqwea")) # False
print(is_unique2("Aaqwe")) # False
print(is_unique2("abc")) # True