def test_is_yml_identifies_regular_string_isnt_yml():
assert not persistence.is_yml('hello,darkness,my,old,friend')
def test_is_yml_identifies_a_dictionary_isnt_yml():
assert not persistence.is_yml({'hello': "i'm not a yml file"})
def test_is_yml_identifies_yaml():
assert persistence.is_yml(os.path.join('path', 'to', 'dir', 'file.yaml'))