wrong use of FIND_PACKAGE_HANDLE_STANDARD_ARGS in dune_python_find_package

I just tried to add the following line to the checks of dune-fempy:

dune_python_find_package(PACKAGE "ufl" REQUIRED VERSION "2016.2")

The test itself does succeed, but I get the following error message:

CMake Error at /usr/share/cmake-3.7/Modules/FindPackageHandleStandardArgs.cmake:219 (message):
  No REQUIRED_VARS specified for FIND_PACKAGE_HANDLE_STANDARD_ARGS()
Call Stack (most recent call first):
  /home/nolte/numerics/master/dune-common/cmake/modules/DunePythonFindPackage.cmake:111 (find_package_handle_standard_args)
  cmake/modules/DuneFempyMacros.cmake:2 (dune_python_find_package)
  /home/nolte/numerics/master/dune-common/cmake/modules/DuneMacros.cmake:579 (include)
  /home/nolte/numerics/master/dune-common/cmake/modules/DuneMacros.cmake:732 (dune_process_dependency_macros)
  CMakeLists.txt:14 (dune_project)

The system in question is Debian Stretch, i.e., CMake 3.7.