class ReeDao::OneToMany

def call(list, assoc_dao, **opts)
  return if list.empty?
  root_ids = list.map(&:id)
  assoc_setter = if opts.key?(:assoc_setter)
    opts[:assoc_setter]
  else
    dto_class = assoc_dao
      .opts[:schema_mapper]
      .dto(:db_load)
    name = underscore(demodulize(dto_class.name))
    "set_#{name}s".to_sym
  end
  foreign_key = if opts.key?(:foreign_key)
    opts[:foreign_key]
  else
    name = underscore(demodulize(list.first.class.name))
    "#{name}_id".to_sym
  end
  assoc_by_group = group_by(assoc_dao.where(foreign_key => root_ids).all) { _1.send(foreign_key) }
  list.each do |item|
    item.send(assoc_setter, assoc_by_group[item.id] || [])
  end
  nil
end