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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 decode_imod(packet, channel=1):
 """Decode an 4 channel imod. May support 6 channels."""

    val = str(packet.get(QSDATA, ''))
    if len(val) == 8 and val.startswith('4e'):
        try:
            _map = ((5, 1), (5, 2), (5, 4), (4, 1), (5, 1), (5, 2))[
                channel - 1]
            return (int(val[_map[0]], 16) & _map[1]) == 0
        except IndexError:
            return None
    return None