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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 join_channels(*channels: Channel) -> Channel: """Join two channels acting on different qubits into a single channel acting on all qubits"""

    vectors = [chan.vec for chan in channels]
    vec = reduce(outer_product, vectors)
    return Channel(vec.tensor, vec.qubits)