Get all labels / entity groups available to a model

I have the following code to get the named entity values from a given text:

from transformers import AutoTokenizer, AutoModelForTokenClassification
from transformers import pipeline

tokenizer = AutoTokenizer.from_pretrained("Davlan/distilbert-base-multilingual-cased-ner-hrl")
model = AutoModelForTokenClassification.from_pretrained("Davlan/distilbert-base-multilingual-cased-ner-hrl")
nlp = pipeline("ner", model=model, tokenizer=tokenizer, aggregation_strategy="max")

example = "My name is Johnathan Smith and I work at Apple"
ner_results = nlp(example)

The following is the output:

[{'end': 26,
  'entity_group': 'PER',
  'score': 0.9994689,
  'start': 11,
  'word': 'Johnathan Smith'},
 {'end': 46,
  'entity_group': 'ORG',
  'score': 0.9983876,
  'start': 41,
  'word': 'Apple'}]

In the above example the labels / entitiy groups are ORG and PER. How to find all the labels / entitiy groups available?
Kindly advise.