Suggestion:  It's a little odd to see the base class for this appearing in a different module that doesn't make use of it.  Though maybe I am missing there is some other use of <code>virttest/utils_libguestfs.py</code> and this is why it is split.  Otherwise, in the interest of keeping code consolidated, consider if maybe this module and/or <code>virttest/utils_libguestfs.py</code> module could be combined in one.  Unless there is a reason I don't see to keep them separate, then you can ignore this.