code: def reference_image_path(cls, project, location, product, reference_image):
          
          return google.api_core.path_template.expand(
              "projects/{project}/locations/{location}/products/{product}/referenceImages/{reference_image}",
              project=project,
              location=location,
              product=product,
              reference_image=reference_image,
          )
docs: Return a fully-qualified reference_image string.