def _flatten(iterable):
    """
    Flatten nested iterable of (tuple, list).
    """
    def rec(iterable):
        for i in iterable:
            if isinstance(i, (tuple, list)):
                for j in rec(i):
                    yield j
            else:
                yield i
    return rec(iterable)

    Flatten nested iterable of (tuple, list).
    
numba/core/datamodel/packer.py