def lazy_array_equiv(arr1, arr2):
    """Like array_equal, but doesn't actually compare values.
    Returns True when arr1, arr2 identical or their dask tokens are equal.
    Returns False when shapes are not equal.
    Returns None when equality cannot determined: one or both of arr1, arr2 are numpy arrays;
    or their dask tokens are not equal
    """
    if arr1 is arr2:
        return True
    arr1 = asarray(arr1)
    arr2 = asarray(arr2)
    if arr1.shape != arr2.shape:
        return False
    if dask_available and is_duck_dask_array(arr1) and is_duck_dask_array(arr2):
        from dask.base import tokenize

        # GH3068, GH4221
        if tokenize(arr1) == tokenize(arr2):
            return True
        else:
            return None
    return None
Like array_equal, but doesn't actually compare values.
    Returns True when arr1, arr2 identical or their dask tokens are equal.
    Returns False when shapes are not equal.
    Returns None when equality cannot determined: one or both of arr1, arr2 are numpy arrays;
    or their dask tokens are not equal
    
xarray/core/duck_array_ops.py