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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 halt(self):
 """Switch state to HALT"""


        buf = []
        buf.append(self.act_end)
        buf.append(0)

        crc = self.calculate_crc(buf)
        self.clear_bitmask(0x08, 0x80)
        self.card_write(self.mode_transrec, buf)
        self.clear_bitmask(0x08, 0x08)
        self.authed = False