[Closed] decent bright(ish) front light for small children's bikes

my partner's 4 year old son has recently learned to properly ride his bike, and as a result wants to go out in the park opposite their house all the time now. he's got a little cheapo silicon/LED front light, but complained to me yesterday that it's not bright enough for him to see where he's going when it gets dark... so, i said i'd sort out a better replacement for it. what do we reckon would fit the bill? needs to be self contained, not too big as it's just a small 14" wheeled bike and doesn't need to be more than probably 50-100 lumens really.