def set_difference(src_A: list, dst_B: list) -> list:
    """returns set difference of src_A and dst_B
    A\\B or A-B = {x: x ∈ A and x ∉ B} a.k.a LEFT OUTER JOIN
    only values in src_A that are NOT in dst_B are returned"""
    diff_list = []
    if isinstance(src_A, list) and isinstance(dst_B, list):
        diff_list = sorted(list(set(src_A) - set(dst_B)))
    return diff_list