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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:
 async def scp_to(self, source, destination, user='ubuntu', proxy=False, scp_opts=''):
 """Transfer files to this unit. :param str source: Local path of file(s) to transfer :param str destination: Remote destination of transferred files :param str user: Remote username :param bool proxy: Proxy through the Juju API server :param scp_opts: Additional options to the `scp` command :type scp_opts: str or list """

        await self.machine.scp_to(source, destination, user=user, proxy=proxy,
                                  scp_opts=scp_opts)