demo.java

private Function<String, String> loadPythonScript() throws IOException {
Source source = Source.newBuilder("python", new File(pythonScriptFile)).build();
Value pyPart = polyglot.eval(source);
Function<String, String> getDepartmentNameByIdFunc = pyPart.getContext().getPolyglotBindings()
.getMember("getDepartmentNameById").as(Function.class);
return getDepartmentNameByIdFunc;
}
// String dname = getDepartmentNameByIdFunc.apply(departmentId);