Function create_material_classification_relationship 

pub fn create_material_classification_relationship(
    tx: &mut Transaction,
    model: &Model,
    classifications: &[EntityId],
    material: EntityId,
) -> MaterialResult<EntityId>

Stage an IfcMaterialClassificationRelationship.

Classifies a material against external systems such as Uniclass or OmniClass. MaterialClassifications is a SET [1:?] (of IfcClassificationSelect, IFC2X3 IfcClassificationNotationSelect), so an unclassified relationship is refused rather than written empty.

Errors

Refuses an empty classification set, and a ClassifiedMaterial that is not an IfcMaterial.