def __repr__(self):
        return "<Requirement(package={package}, version='{version}')>".format(
            package=self.package, version=self.version)
def remove_backend(self, backend_id):
        """ Removes a backend from the treeview, and selects the first (to show
        something in the configuration panel

        @param backend_id: the id of the backend to remove
        """
        if backend_id in self.backendid_to_iter:
            self.liststore.remove(self.backendid_to_iter[backend_id])
            del self.backendid_to_iter[backend_id]
            self.select_backend()