Sets the working directory for this hypervisor.

        :param working_dir: path to the working directory

def set_working_dir(self, working_dir):
        """
        Sets the working directory for this hypervisor.

        :param working_dir: path to the working directory
        """

        # encase working_dir in quotes to protect spaces in the path
        yield from self.send('hypervisor working_dir "{}"'.format(working_dir))
        self._working_dir = working_dir
        log.debug("Working directory set to {}".format(self._working_dir))