def extend(self, iterable):
        """Extend call list if all in iterable are callable.

        Extends list.extend.
        """
        if not all(map(callable, iterable)):
            raise ValueError("All items must be callable")

        else:
            super().extend(iterable)
Extend call list if all in iterable are callable.

        Extends list.extend.
        
nodezator/ourstdlibs/collections/general.py