tim whewell reports now from iraq on the children left behind by the fighters of islamic state.tting. # if you're happy, happy, happy # clap your hands...# in a classroom in northern iraq, they're singing to overcome their memories. these nine and ten—year—olds were all captives of so—called islamic state, where music was haram — forbidden. from their smiles, you might not guess the violence they've seen, but they're all scarred by it. isis enslaved this boy and his sister three years ago. so what did they tell you about the guns? the children at this rehabilitation centre are yazidi, part of the non—muslim minority singled out for particular cruelty by isis. in 2014, their villages were seized and thousands of men murdered on the spot. the women were sold into slavery, and children taken for re—education to serve the so—called caliphate. what did they say about your family? when first they talk about their experience, it was not actually easy and good, but now they can express it in a different way. at first they were just too scared to talk about it. now they can talk about it