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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 write_pid(self, pid):
 """ Write pid to the pid file :param pid: pid of the process :type pid: None | int :return: None """

        self.fpid.seek(0)
        self.fpid.truncate()
        self.fpid.write("%d" % pid)
        self.fpid.close()
        del self.fpid