Checks if string is isogram

def is_isogram(string):
    unique_list=[]
    for each_letter in string.lower():
        if each_letter in unique_list:
            return False
        else:
            unique_list.append(each_letter)
    return True

text="mytext"

if is_isogram(text):
    print("True")
else:
    print("False")