Function cover_elements 

pub fn cover_elements(
    tx: &mut Transaction,
    global_id: &str,
    element: EntityId,
    coverings: &[EntityId],
) -> SpatialAuthoringResult<EntityId>

Stage an IfcRelCoversBldgElements: finishes applied to an element.

Kept apart from cover_spaces because the same covering can do both, and the two answer different questions: which finishes are on this wall, versus which finishes bound this space.

Errors

Refuses a malformed GlobalId, an empty covering set, and the element listed among its own coverings.