Avoid bare except clauses if at all possible.  There appear to be two obvious failure cases here, which may mean different things.  The first is if the config_form module doesn't exist and the second is if the ConfigForm class doesn't exist within the module.  But there may also be other unexpected failure cases (circular imports, syntax error in the module, etc) and this bare clause will catch them all.

In the future, developing new themes will be hindered by this.