def METHOD_NAME(self, mode, virt=None, get_default_virt=False):
    """
    Gets a installer class that should be able to install the virt software
    Always try to use classes that are specific to the virtualization
    technology that is being tested. If you have confidence that the
    installation is rather trivial and does not require custom steps, you
    may be able to get away with a base class (by setting get_default_virt
    to True).
    """
    if virt is None:
        virt = self.DEFAULT_VIRT_NAME
    if virt not in self:
        # return a base installer so the test could and give it a try?
        if get_default_virt:
            return self[self.DEFAULT_VIRT_NAME].get(mode)
    else:
        return self[virt].get(mode)