request is the output of translate_check. models a dict of {(model_name,pkey_tuple):model}.\
  ICF is a {model_name:fields_list} for which we want to add nulls in request for missing children. see AMC for how it's used.\
  The caller should have gone through the same ICF logic when looking up models so the arg has all the refs the DB knows.\
  modelgb is misc.GetterBy<ModelInfo>, used by AMC for resolution.

def do_check(pool,request,models,include_children_for,modelgb):
  "request is the output of translate_check. models a dict of {(model_name,pkey_tuple):model}.\
  ICF is a {model_name:fields_list} for which we want to add nulls in request for missing children. see AMC for how it's used.\
  The caller should have gone through the same ICF logic when looking up models so the arg has all the refs the DB knows.\
  modelgb is misc.GetterBy<ModelInfo>, used by AMC for resolution."
  add_missing_children(models,request,include_children_for,modelgb)
  return {k:fkapply(models,pool,process_check,None,k,v) for k,v in request.items()}