Ollie: "We've gotta help that old lady."
Stan: "I wish we could."
Ollie: "One good turn deserves another."
Stan: "So do I, neither."
Ollie: "What do you mean, "So do I, neither"?
They're going to throw her into the streets."
My question is the same as Ollie's - what Stan does mean with "So do I, neither"?