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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def set_seq2(self, b):
 """Same as SequenceMatcher.set_seq2, but uses the c chainb implementation. """

        if b is self.b and hasattr(self, 'isbjunk'):
            return
        self.b = b
        if not isinstance(self.a, list):
            self.a = list(self.a)
        if not isinstance(self.b, list):
            self.b = list(self.b)

        # Types must be hashable to work in the c layer.  This check lines will
        # raise the correct error if they are *not* hashable.
        [hash(x) for x in self.a]
        [hash(x) for x in self.b]

        self.matching_blocks = self.opcodes = None
        self.fullbcount = None
        junk, popular = _cdifflib.chain_b(self)
        assert hasattr(junk, '__contains__')
        assert hasattr(popular, '__contains__')
        self.isbjunk = junk.__contains__
        self.isbpopular = popular.__contains__