Python classmethod - why does this not pass? I get the correct pattern in my workspace.

class Letter:
    def __init__(self, pattern=None):
        self.pattern = pattern

    def __iter__(self):
        yield from self.pattern

    def __str__(self):
        output = []
        for blip in self:
            if blip == '.':
                output.append('dot')
            else:
                output.append('dash')
        return '-'.join(output)

    @classmethod
    def from_string(cls, item):
        x = []
        x = item.split("-")
        length = len(x)
        count = 0
        if count < length:
            if x[count] == "dash":
                x[count] = "_"
                count = count + 1
            if x[count] == "dot":
                x[count] = "."
            count = count + 1
        return cls(x)





class S(Letter):
    def __init__(self):
         pattern = ['.', '.', '.']
         super().__init__(pattern)