def METHOD_NAME(b_obj):
    """Scale a single face of the object."""
    # scale single face
    for poly in b_obj.data.polygons:
        poly.select = False
    b_obj.data.polygons[2].select = True
    for b_vert_index in b_obj.data.polygons[2].vertices:
        b_obj.data.vertices[b_vert_index].co[1] = b_obj.data.vertices[b_vert_index].co[1] * 0.5
        b_obj.data.vertices[b_vert_index].co[2] = b_obj.data.vertices[b_vert_index].co[2] * 0.5