Maltese X Poodles, or "Maltipoo" are not purebred anyway, they're not a recognised breed, they're a mixed breed.
Plus if the breed is selling it at 5 weeks old, I wouldn't get it anyway because that is far too young to separate the pup from its mum, which suggests the breeder isn't necessarily a "good breeder". A pup that small, shouldn't be sold until it is at least 7-8 weeks old.
If you're worried about the breeder being honest about the pup's breeding though, don't get it.
Plus if the breed is selling it at 5 weeks old, I wouldn't get it anyway because that is far too young to separate the pup from its mum, which suggests the breeder isn't necessarily a "good breeder". A pup that small, shouldn't be sold until it is at least 7-8 weeks old.
If you're worried about the breeder being honest about the pup's breeding though, don't get it.