Install one NApp using NAppManager object.

def enable_napp(cls, mgr):
        """Install one NApp using NAppManager object."""
        try:
            if not mgr.is_enabled():
                LOG.info('    Enabling...')
                mgr.enable()
            LOG.info('    Enabled.')
        except (FileNotFoundError, PermissionError) as exception:
            LOG.error('  %s', exception)