Load external plugins.

        Custodian is intended to interact with internal and external systems
        that are not suitable for embedding into the custodian code base.

def load_plugins(self):
        """ Load external plugins.

        Custodian is intended to interact with internal and external systems
        that are not suitable for embedding into the custodian code base.
        """
        try:
            from pkg_resources import iter_entry_points
        except ImportError:
            return
        for ep in iter_entry_points(group="custodian.%s" % self.plugin_type):
            f = ep.load()
            f()