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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 _contains_line(self, line):
 """Test if a chain of qubits is completely contained in ``self``. In particular, test if all qubits are present and the couplers connecting those qubits are also connected. NOTE: this function assumes that ``line`` is a list or tuple of qubits which satisfies the precondition that ``(line[i],line[i+1])`` is supposed to be a coupler for all ``i``. INPUTS: line: a list of qubits satisfying the above precondition OUTPUT: boolean """

        return all(v in self for v in line) and all(u in self[v] for u, v in zip(line, line[1::]))