code: def set_children(self, child_ids):
          
          if not isinstance(child_ids, list):
              raise errors.InvalidArgument()
          if self.get_children_metadata().is_read_only():
              raise errors.NoAccess()
          idstr_list = []
          for object_id in child_ids:
              if not self._is_valid_id(object_id):
                  raise errors.InvalidArgument()
              if str(object_id) not in idstr_list:
                  idstr_list.append(str(object_id))
          self._my_map['childIds'] = idstr_list
docs: Sets the children.
  
          arg:    child_ids (osid.id.Id[]): the children``Ids``
          raise:  InvalidArgument - ``child_ids`` is invalid
          raise:  NoAccess - ``Metadata.isReadOnly()`` is ``true``
          *compliance: mandatory -- This method must be implemented.*