code: def test_register_processor_variant():
      nlp = stanza.Pipeline(
          dir=TEST_MODELS_DIR,
          lang="en",
          processors={"tokenize": "lol"},
          package=None,
      )
      doc = nlp(EN_DOC)
      assert EN_DOC_LOL_TOKENS == "\n\n".join(
          sent.tokens_string() for sent in doc.sentences
      )
  
imports: import pytest
  import stanza
  from stanza.models.common.doc import Document
  from stanza.pipeline.core import PipelineRequirementsException
  from stanza.pipeline.processor import Processor, ProcessorVariant, register_processor, register_processor_variant, ProcessorRegisterException
  from stanza.utils.conll import CoNLL
  from stanza.tests import *
label_desc: Use image node_id 3 for calling a global function with example usage: test_register_processor_variant() without return types