def add_permissions(self, grp_name, resource, permissions):
        """
        Add additional permissions for the group associated with the resource.

        Args:
            grp_name (string): Name of group.
            resource (intern.resource.boss.Resource): Identifies which data
                model object to operate on.
            permissions (list): List of permissions to add to the given resource

        Raises:
            requests.HTTPError on failure.
        """
        self.project_service.set_auth(self._token_project)
        self.project_service.add_permissions(grp_name, resource, permissions)
Add additional permissions for the group associated with the resource.

        Args:
            grp_name (string): Name of group.
            resource (intern.resource.boss.Resource): Identifies which data
                model object to operate on.
            permissions (list): List of permissions to add to the given resource

        Raises:
            requests.HTTPError on failure.