code: def test_email_search_key_detection_by_values():
      df = pd.DataFrame(
          {"eml": ["asdf@asdf.sad", "woei@skdjfh.fnj"] + ["12@3"] * 8}
      )
  
      assert detector.get_search_key_column(df) == "eml"
  
      df = pd.DataFrame({"eml": ["asdf@asdf.sad"] + ["12@"] * 9})
  
      maybe_search_key_column = detector.get_search_key_column(df)
      print(maybe_search_key_column)
      assert maybe_search_key_column is None
  
      df = pd.DataFrame({"eml": [1, 2, 3, 4, 5]})
  
      assert detector.get_search_key_column(df) is None
  
file_path: upgini/tests/test_email_utils.py
imports: import pandas
  from pandas.testing import assert_frame_equal
  from upgini.metadata import SearchKey
  from upgini.utils.email_utils import EmailSearchKeyConverter, EmailSearchKeyDetector
label_desc: Use image node_id 2 for calling a global function with example usage: test_email_search_key_detection_by_values() without return types