Sometimes (In my case for a plugin-like structure) you start with the following:

├── plugins 

__all__ = ['plug_a', 'plug_b']

Ready, right?

from plugins import *

for modname, mod in sys.modules.iteritems():
        if modname.startswith(plugins.__name__):
        # run plugin or whatever

That's good and all, but if there were problems in any of these plugins, it would fail when we do a from plugins import *. So instead:

for plugin in plugins.__all__:
        __import__('{}.{}'.format(plugins.__name__, plugin))
        print plugin, 'could not be loaded'

The except is a little broad and could be narrowed to ImportError maybe, but who knows what else could hide in there.