def __init__(self, *args, **kwargs):
        """Check callable state of items.

        Extends list.__init__
        """
        super().__init__(*args, **kwargs)

        if not all(map(callable, self)):
            raise ValueError("All items must be callable")
Check callable state of items.

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