Jython function to java Consumer

I want to give a python function as a Consumer for a java method.

public Class MyObject {
    public void javaFunction(Consumer<Double> consumer){...}
}

and

def python_function(arg):
    some_code_using(arg)

I tried the following:

myObjectInstance.javaFunction(python_function)

and

myObjectInstance.javaFunction(lambda arg: python_function(arg))

Each time, I get 1st arg can't be coerced to java.util.function.Consumer

I've done this before with Suppliers and it worked well. I'm using org.python.util.PythonInterpreter

Any ideas on how to pass such a Consumer ?