def _get_non_empty_list(cls, iter):
        """Return a list of the input, excluding all ``None`` values."""
        res = []
        for value in iter:
            if hasattr(value, 'items'):
                value = cls._get_non_empty_dict(value) or None
            if value is not None:
                res.append(value)
        return res
Return a list of the input, excluding all ``None`` values.