How to simultaneously use getter and setter of spaCy Property extensions.

[mrsniperz]

From the documentation, it can be inferred that when using a getter to retrieve a property value, if you want to modify it, you need to set a setter simultaneously. However, when I use both getter and setter, I'm not sure how to write this function. Please see the example below, which throws an error when executed.

import spacy
from spacy.tokens import Doc

def get_extension(doc):
    return 'Hello, World!'

def set_extension(doc, value):
    doc._.token_scores = value

Doc.set_extension("token_scores", getter=get_extension, setter=set_extension)

nlp = spacy.blank("en")

doc = nlp("This is a test document.")

doc._.token_scores = 'HI'

print(doc._.token_scores)

The error message is as follows:
RecursionError: maximum recursion depth exceeded

[mrsniperz]

Has any one met this problem?