def check_plugins(self):
        """ collect plugins from entry point 'frosted.plugins'

        and run their check() method, passing the filename
        """
        checkers = {}
        for ep in pkg_resources.iter_entry_points(group='frosted.plugins'):
            checkers.update({ep.name: ep.load()})

        for plugin_name, plugin in checkers.items():
            if self.filename != '(none)':
                messages = plugin.check(self.filename)
                for message, loc, args, kwargs in messages:
                    self.report(message, loc, *args, **kwargs)
collect plugins from entry point 'frosted.plugins'

        and run their check() method, passing the filename