'Mount a disk image, using the object attributes.
The first supported means provided by the mount classes is used.
True, or False is returned and the \'errors\' attribute
contains any diagnostics.'

def mount(self):

    if self._mounter:
        raise exception.NovaException(_('image    already    mounted'))
    if (not self.mount_dir):
        self.mount_dir = tempfile.mkdtemp(prefix=self.tmp_prefix)
        self._mkdir = True
    mounter = mount.Mount.instance_for_format(self.image, self.mount_dir, self.partition)
    if mounter.do_mount():
        self._mounter = mounter
        return self._mounter.device
    else:
        LOG.debug(mounter.error)
        self._errors.append(mounter.error)
        return None
