Simple Python plugin loader

I have written a simple system to load plugins from files in Python 2.7, and I'd like to see if any of it can be improved upon.

vedo.py

from __future__ import absolute_import

import os.path
import inspect

from vedo.event_emitter import EventEmitter
from vedo import VedoPlugin


def _get_module_name(directory, filename):
    return '{0}.{1}'.format(os.path.basename(directory), filename)


def _is_plugin_class(plugin_class):
    return (inspect.isclass(plugin_class) and
            issubclass(plugin_class, VedoPlugin) and
            plugin_class != VedoPlugin)


class Vedo(EventEmitter):
    def __init__(self, plugin_directory):
        self._plugin_directory = plugin_directory
        self._plugins = []

    @property
    def plugin_directory(self):
        return self._plugin_directory

    @property
    def plugins(self):
        return self._plugins

    def load_module(self, module):
        plugin_classes = [c for c in module.__dict__.values() if
                          _is_plugin_class(c)]

        for plugin_class in plugin_classes:
            self.plugins.append(plugin_class(self))

    def load_file(self, name):
        try:
            plugin_module = _get_module_name(self._plugin_directory, name)
            namespace = __import__(plugin_module)
        except ImportError:
            return

        self.load_module(getattr(namespace, name))

Each plugin must inherit from VedoPlugin, and is loaded by the Vedo class.

Here's an example plugin:

plugins/first.py

class MyFirstPlugin(VedoPlugin):
    def __init__(self, vedo):
        super(MyFirstPlugin, self).__init__(vedo)

And a quick example of how to use Vedo:

vedo = Vedo("./plugins")
vedo.load_file("first")

vedo.plugins[0] # This is an instance of `MyFirstPlugin'

Here's some things I'm not too fond of, but I'm not sure what I can do about them:

• Should the private functions in the top of vedo.py be moved inside the Vedo class?
• Should load_module be private? It's only really going to be used when loading files.
• Is there a way to get around the ugliness that is the plugin __init__ function? Every single plugin will need to have that constructor, which I'm not too happy about.