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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 bandpass_filter(rate=None, low=None, high=None, order=None):
 """Butterworth bandpass filter."""

    assert low < high
    assert order >= 1
    return signal.butter(order,
                         (low / (rate / 2.), high / (rate / 2.)),
                         'pass')