code: def _email_to_one_domain(email: str) -> Optional[str]:
      if email is not None and isinstance(email, str) and "@" in email:
          name_and_domain = email.split("@")
          if (
              len(name_and_domain) == 2
              and len(name_and_domain[0]) > 0
              and len(name_and_domain[1]) > 0
          ):
              return name_and_domain[0][0] + name_and_domain[1]
  
file_path: upgini/src/upgini/utils/email_utils.py
imports: import logging
  import re
  from hashlib import sha256
  from typing import Dict, List, Optional
  import pandas
  from pandas.api.types import is_string_dtype
  from upgini.resource_bundle import bundle
  from upgini.metadata import SearchKey
  from upgini.utils.base_search_key_detector import BaseSearchKeyDetector
label_desc: Use image node_id 3 for calling the EmailSearchKeyConverter obj's underlying member method code with example usage: obj._email_to_one_domain(email) and returns: unknown