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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 posix_rename(self, oldpath, newpath):
 """ Rename a file or folder from ``oldpath`` to ``newpath``, following posix conventions. :param str oldpath: existing name of the file or folder :param str newpath: new name for the file or folder, will be overwritten if it already exists :raises: ``IOError`` -- if ``newpath`` is a folder, posix-rename is not supported by the server or something else goes wrong :versionadded: 2.2 """

        oldpath = self._adjust_cwd(oldpath)
        newpath = self._adjust_cwd(newpath)
        self._log(DEBUG, "posix_rename({!r}, {!r})".format(oldpath, newpath))
        self._request(
            CMD_EXTENDED, "posix-rename@openssh.com", oldpath, newpath
        )