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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 _valid_packet(raw_packet):
 """Validate incoming packet."""

        if raw_packet[0:1] != b'\xcc':
            return False
        if len(raw_packet) != 19:
            return False
        checksum = 0
        for i in range(1, 17):
            checksum += raw_packet[i]
        if checksum != raw_packet[18]:
            return False
        return True