from scheduler.block import BaseBlock


class UniqueList(BaseBlock):
    def __call__(self, input: list) -> list:
        return list(set(input))


class HeadOfList(BaseBlock):
    def __call__(self, input: list) -> str:
        if len(input) > 0:
            return input[0]
        else:
            return None


class ReverseList(BaseBlock):
    def __call__(self, input: list) -> list:
        l = input[:]
        l.reverse()
        return l


class TailOfList(BaseBlock):
    def __call__(self, input: list) -> list:
        return input[1:]


class LengthOfList(BaseBlock):
    def __call__(self, input: list) -> int:
        return len(input)


class ConcatList(BaseBlock):
    def __call__(self, seq1: list, seq2: list) -> list:
        return seq1 + seq2