def METHOD_NAME(obj: MeshObject, collection_of_mats: Dict[str, Dict[str, Material]],
                          ceiling_emission_strength: float = 1.5):
    """ Makes the given ceiling object emissive, s.t. there is always a little bit ambient light.
    :param obj: The ceiling object.
    :param collection_of_mats: A dictionary that contains materials for lamps, windows and ceilings.
    :param ceiling_emission_strength: The emission strength that should be used for the ceiling. Default: 1.5
    """
    for i, material in enumerate(obj.get_materials()):
        if material is None:
            continue
        mat_name = material.get_name()
        if mat_name in collection_of_mats["ceiling"]:
            # this material was used as a ceiling before use that one
            obj.set_material(i, collection_of_mats["ceiling"][mat_name])
            continue
        # copy the material if more than one user is using it
        if material.get_users() > 1:
            material = material.duplicate()
            obj.set_material(i, material)
        # rename the material
        material.set_name(material.get_name() + "_emission")
        if not material.get_nodes_with_type("Emission") and material.get_nodes_with_type("BsdfPrincipled"):
            material.make_emissive(emission_strength=ceiling_emission_strength, emission_color=[1, 1, 1, 1])
            collection_of_mats["ceiling"][mat_name] = material