def METHOD_NAME(node: Union[nodes.For, nodes.Comprehension]) -> bool:
    """Return whether the index variable in the for loop/comprehension is ONLY used to index the iterable.
    True if unnecessary usage, False otherwise or if index variable not used at all.
    """
    index_nodes = []
    for assign_name_node in node.target.nodes_of_class((nodes.AssignName, nodes.Name)):
        index_nodes.extend(_index_name_nodes(assign_name_node.name, node))
    return all(_is_redundant(index_node, node) for index_node in index_nodes) and index_nodes