code: def test_is_postal_code_column_by_column_name():
      df = pd.DataFrame({"pstlcd": ["123", "321", "345"]})
  
      assert detector.get_search_key_column(df) is None
  
      df = pd.DataFrame({"zip": ["123", "321", "345"]})
  
      assert detector.get_search_key_column(df) == "zip"
  
      df = pd.DataFrame({"zipcode": ["123", "321", "345"]})
  
      assert detector.get_search_key_column(df) == "zipcode"
  
      df = pd.DataFrame({"zip_code": ["123", "321", "345"]})
  
      assert detector.get_search_key_column(df) == "zip_code"
  
      df = pd.DataFrame({"postal_code": ["123", "321", "345"]})
  
      assert detector.get_search_key_column(df) == "postal_code"
  
      df = pd.DataFrame({"postalcode": ["123", "321", "345"]})
  
      assert detector.get_search_key_column(df) == "postalcode"
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_is_postal_code_column_by_column_name() without return types