code: def test_email_to_hem_convertion():
      df = pd.DataFrame(
          [
              {"email": "test@google.com"},
              {"email": None},
              {"email": "fake"},
          ]
      )
      search_keys = {
          "email": SearchKey.EMAIL,
      }
      converter = EmailSearchKeyConverter("email", None, search_keys)
      df = converter.convert(df)
      assert EmailSearchKeyConverter.HEM_COLUMN_NAME in df.columns
      assert EmailSearchKeyConverter.DOMAIN_COLUMN_NAME in df.columns
      assert (
          EmailSearchKeyConverter.EMAIL_ONE_DOMAIN_COLUMN_NAME
          in df.columns
      )
      assert "email" in df.columns
      assert converter.email_converted_to_hem
  
imports: import ipaddress
  import random
  from datetime import date, datetime
  import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
  from upgini import Dataset, FileColumnMeaningType
  from upgini.errors import ValidationError
  from upgini.metadata import ModelTaskType, SearchKey
  from upgini.resource_bundle import bundle
  from upgini.utils.datetime_utils import DateTimeSearchKeyConverter
  from upgini.utils.email_utils import EmailSearchKeyConverter
  from upgini.utils.features_validator import FeaturesValidator
  from upgini.utils.warning_counter import WarningCounter
label_desc: Use image node_id 2 for calling a global function with example usage: test_email_to_hem_convertion() without return types