Registers plugin classes, which are in sys.path and have an entry_point called 'groundwork.plugin'.
        :return: dict of plugin classes

def _get_plugins_by_entry_points(self):
        """
        Registers plugin classes, which are in sys.path and have an entry_point called 'groundwork.plugin'.
        :return: dict of plugin classes
        """
        # Let's find and register every plugin, which is in sys.path and has defined a entry_point 'groundwork.plugin'
        # in it's setup.py
        entry_points = []
        classes = {}
        for entry_point in iter_entry_points(group='groundwork.plugin', name=None):
            entry_points.append(entry_point)

        for entry_point in entry_points:
            try:
                entry_point_object = entry_point.load()
            except Exception as e:
                # We should not throw an exception now, because a package/entry_point can be outdated, using an old
                # api from groundwork, tries to import unavailable packages, what ever...
                # We just do not make it available. That's all we can do.
                self._log.debug("Couldn't load entry_point %s. Reason: %s" % (entry_point.name, e))
                continue

            if not issubclass(entry_point_object, GwBasePattern):
                self._log.warning("entry_point  %s is not a subclass of groundworkPlugin" % entry_point.name)
                continue
            plugin_name = entry_point_object.__name__

            plugin_class = self.register_class(entry_point_object, plugin_name,
                                               entrypoint_name=entry_point.name,
                                               distribution_path=entry_point.dist.location,
                                               distribution_key=entry_point.dist.key,
                                               distribution_version=entry_point.dist.version)

            classes[plugin_name] = plugin_class
            # classes[plugin_name] = {
            #     "name": plugin_name,
            #     "entry_point": entry_point.name,
            #     "path": entry_point.dist.location,
            #     "class": entry_point_object,
            #     "distribution": {
            #         "key": entry_point.dist.key,
            #         "version": entry_point.dist.version
            #     },
            # }
            self._log.debug("Found plugin: %s at entry_point %s of package %s (%s)" % (plugin_name, entry_point.name,
                                                                                       entry_point.dist.key,
                                                                                       entry_point.dist.version))
        return classes