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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 upload(self, filename, input, packethook=None, timeout=SOCK_TIMEOUT):
 """This method initiates a tftp upload to the configured remote host, uploading the filename passed. It reads the file from input, which can be a file-like object or a path to a local file. If a packethook is provided, it must be a function that takes a single parameter, which will be a copy of each DAT packet sent in the form of a TftpPacketDAT object. The timeout parameter may be used to override the default SOCK_TIMEOUT setting, which is the amount of time that the client will wait for a DAT packet to be ACKd by the server. Note: If input is a hyphen, stdin is used."""

        self.context = TftpContextClientUpload(self.host,
                                               self.iport,
                                               filename,
                                               input,
                                               self.options,
                                               packethook,
                                               timeout,
                                               localip = self.localip)
        self.context.start()
        # Upload happens here
        self.context.end()

        metrics = self.context.metrics

        log.info('')
        log.info("Upload complete.")
        if metrics.duration == 0:
            log.info("Duration too short, rate undetermined")
        else:
            log.info("Uploaded %d bytes in %.2f seconds" % (metrics.bytes, metrics.duration))
            log.info("Average rate: %.2f kbps" % metrics.kbps)
        log.info("%.2f bytes in resent data" % metrics.resent_bytes)
        log.info("Resent %d packets" % metrics.dupcount)