class ReeMapper::Array

def db_load(value, role: nil)
  if value.is_a?(Array)
    value.map {
      if _1.nil? && of.null
        _1
      else
        of.type.db_load(_1, role: role)
      end
    }
  else
    raise ReeMapper::TypeError, "should be an array"
  end
end