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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 _imul(self, n):
 """Concatenate n copies of self in place. Return self."""

        assert n >= 0
        if not n:
            self._clear()
            return self
        m = 1
        old_len = self.len
        while m * 2 < n:
            self._append(self)
            m *= 2
        self._append(self[0:(n - m) * old_len])
        return self