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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 concat(self, one, two):
 """Multiply two matrices and replace current one."""

        if not len(one) == len(two) == 6:
            raise ValueError("bad sequ. length")
        self.a, self.b, self.c, self.d, self.e, self.f = TOOLS._concat_matrix(one, two)
        return self