code: def epoch_to_dttm(cls) -> str:
      return "dateadd(S, {col}, '1970-01-01')"
  
file_path: superset/superset/db_engine_specs/mssql.py
imports: import logging
  import re
  from datetime import datetime
  from re import Pattern
  from typing import Any, Optional
  from flask_babel import gettext
  from sqlalchemy import types
  from sqlalchemy.dialects.mssql.base import SMALLDATETIME
  from superset.constants import TimeGrain
  from superset.db_engine_specs.base import BaseEngineSpec, LimitMethod
  from superset.errors import SupersetErrorType
  from superset.utils.core import GenericDataType
label_desc: Use image node_id 1 for calling the MssqlEngineSpec obj's underlying member method code with example usage: obj.epoch_to_dttm(cls) and returns: str