code: def test_get_lang():
      sentence = "This is a test sentence."
      expected_lang = "en"
      threshold_prob = 0.99
  
      lang = get_language(sentence)
  
      assert lang[0] == expected_lang
      assert lang[1] > threshold_prob
  
      lang = get_language("a")
      assert lang[0] == "unknown"
      assert lang[1] == 0.0
  
file_path: doctr/tests/common/test_models.py
imports: from io import BytesIO
  import cv2
  import numpy
  import pytest
  import requests
  from doctr.io import reader
  from doctr.models._utils import estimate_orientation, get_language, invert_data_structure
  from doctr.utils import geometry
label_desc: Use image node_id 4 for calling a global function with example usage: test_get_lang() without return types