from typing import MutableSequence
from typing import Hashable


def is_tree(item: object) -> bool:
    """Returns whether 'item' is a tree.

    Args:
        item (object): instance to test.

    Returns:
        bool: whether 'item' is a tree.
    
    """
    return (
        isinstance(item, MutableSequence)
        and all(isinstance(i, (MutableSequence, Hashable)) for i in item))