def is_compatible_symbolic_vector(val_a, val_b):
    """
    compare two vector and check if they are compatible.
    ([is0, 4], [9, 4]), ([is0, 1],[is1, is2]) are twp compatible examples.
    """
    val_a = tuple(val_a)
    val_b = tuple(val_b)

    if len(val_a) != len(val_b):
        return False

    for a, b in zip(val_a, val_b):
        if not is_symbolic(a) and not is_symbolic(b):
            if a != b:
                return False
    return True

    compare two vector and check if they are compatible.
    ([is0, 4], [9, 4]), ([is0, 1],[is1, is2]) are twp compatible examples.
    
coremltools/converters/mil/mil/types/symbolic.py