code: def get_session() -> Session:
      """Fetch a SQLAlchemy session with a connection to a DB.
  
      Returns:
          Session: an instance of a SQLAlchemy session.
  
      """
      global SESSION_FACTORY
      if SESSION_FACTORY is None:
          init_engine_and_session_factory()
      assert SESSION_FACTORY is not None
      # pyre-fixme[29]: `Session` is not a function.
      return SESSION_FACTORY()
  
file_path: Ax/ax/storage/sqa_store/db.py
imports: from __future__ import annotations
  from contextlib import contextmanager
  from typing import Any, Callable, Generator, Optional, TypeVar
  from sqlalchemy import create_engine
  from sqlalchemy.engine.base import Engine
  from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy.orm import scoped_session, Session, sessionmaker
label_desc: Use image node_id 7 for calling a global function with example usage: get_session() and returns: SESSION_FACTORY