def _has_double_couples(s):
couples = util.slide(2, s)
couple_groups = [
list(value)
for key, value
in itertools.groupby(
sorted(
enumerate(couples),
key=lambda (_, letters): letters
),
key=lambda (_, letters): letters
)
]
def _has_double_letters_with_middle(s):
return any([True for a, _, c in util.slide(3, s) if a == c])
def _has_double_letters(s):
return any((True for a, b in util.slide(2, s) if a == b))