def load(self, filename, create_if_missing=True):
        filename = Path(filename)
        if not filename.exists() and create_if_missing:
            self.load_pip_requirements()
            with filename.open("w") as f:
                f.write(yaml.dump(self.serialized, default_flow_style=False,
                                  encoding=None))
            self.filename = filename
            return self.save(filename)
        with filename.open() as f:
            for group, requirements in yaml.load(f.read()).items():
                for requirement in requirements:
                    self[group].add(Requirement.coerce(requirement))
        self.filename = filename
def enable_plugin(plugin):
    plugin = get_plugin_from_all(plugin)

    if plugin.enabled:
        flash(_("Plugin %(plugin)s is already enabled.", plugin=plugin.name),
              "info")
        return redirect(url_for("management.plugins"))

    try:
        plugin.enable()
        flash(_("Plugin %(plugin)s enabled. Please restart FlaskBB now.",
                plugin=plugin.name), "success")
    except OSError:
        flash(_("It seems that FlaskBB does not have enough filesystem "
                "permissions. Try removing the 'DISABLED' file by "
                "yourself instead."), "danger")

    return redirect(url_for("management.plugins"))