I don't think it's the breed you should worry about, but the dog itself. They all are different and have different personalities and past history(if taken from a rescue shelter).
But you should know that any dog can bite, even the ones that looked really patient and seem not to bother when kids pull their hair. Kids around dogs should ALWAYS be supervised.
I a lot of bite cases, the dog didn't look like he was bothered by the kid, but he was sending body messages that often are not understood by the parents nor the kids. Those signs when ignored can rapidly escalate to growling and then biting. A lot of parents , when a bit accident happened, said that their dog never bit before and that they just bit out of nowhere. But, the dog was in fact giving a lot of warning signs that weren't acknowledged.
I recommend you get a dog from a shelter since they know better the personality of the dog and if they will go well with kids, and also because when you get a puppy, you don't know yet his adult personality.
I also recommend you look up for "Calming signals" on google or youtube to learn the dog language so you can prevent any biting accident.
It's also the parents job to teach their kids how to respect the dog space and needs so the dog don't lose his patience and an accident happens.