# currently, it's not possible because related_key_dict is indexed by related key name, which makes 'source_title_1' lookup fail. It should be indexed by group (probably).
# currently, it's not possible because related_key_dict is indexed by related key name, which makes 'source_title_1' lookup fail. It should be indexed by group (probably).
# TODO: rename all "related_key" references into "virtual_column"
# TODO: rename all "related_key" references into "virtual_column"