The initial aim of the dis.Positions was to provide an interface like AST nodes. So you could do

for instr in dis.Bytecode(source):
    print("located in: ", instr.positions.lineno)

instead of

for instr in dis.Bytecode(source):
    if instr.positions:
        lineno = instr.positions[0]
    else:
        lineno = None
    print("located in: ", lineno)

I think this is a bug that we are not currently using it, I'd say we should use it properly and go with option 2.