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


import codewars_test as test
from solution import is_isogram

@test.describe("Fixed Tests")
def fixed_tests():
    @test.it('Basic Test Cases')
    def basic_test_cases():      
        test.assert_equals(is_isogram("Dermatoglyphics"), True )
        test.assert_equals(is_isogram("isogram"), True )
        test.assert_equals(is_isogram("aba"), False, "same chars may not be adjacent" )
        test.assert_equals(is_isogram("moOse"), False, "same chars may not be same case" )
        test.assert_equals(is_isogram("isIsogram"), False )
        test.assert_equals(is_isogram(""), True, "an empty string is a valid isogram" )