def delete_elements(bdf_model, element_types_to_save=None):
    """early version of way to delete specific element cards"""
    eids_to_delete = set()
    if element_types_to_save:
        for eid, element in bdf_model.elements.items():
            etype = element.type
            if etype not in element_types_to_save:
                eids_to_delete.add(eid)
                bdf_model._type_to_id_map[etype].remove(eid)
    for eid in eids_to_delete:
        del bdf_model.elements[eid]
