    def push_scope(self, scope):
        """
        Enter a given sub-scope.

        Treats further dereferences as being performed underneath the
        given scope.
        """
        self._scopes_stack.append(
            self._urljoin_cache(self.resolution_scope, scope),
        )
Enter a given sub-scope.

Treats further dereferences as being performed underneath the
given scope.
jsonschema/validators.py