code: def init(connection_str: str = None):
      global Base, session, engine
      if connection_str is None:
          connection_str = os.environ["MINDSDB_DB_CON"]
      base_args = {
          "pool_size": 30,
          "max_overflow": 200,
          "json_serializer": CustomJSONEncoder().encode,
      }
      engine = create_engine(connection_str, echo=False, **base_args)
      session = scoped_session(
          sessionmaker(bind=engine, autoflush=True)
      )
      Base.query = session.query_property()
  
imports: import datetime
  import json
  import os
  from typing import Dict, List
  import numpy
  from sqlalchemy import JSON, Boolean, Column, DateTime, Index, Integer, String, Table, UniqueConstraint, create_engine, text, types
  from sqlalchemy.exc import OperationalError
  from sqlalchemy.orm import Mapped, declarative_base, relationship, scoped_session, sessionmaker
  from sqlalchemy.sql.schema import ForeignKey
  from mindsdb.utilities.json_encoder import CustomJSONEncoder
label_desc: Use image node_id 1 for calling a global function with example usage: init(connection_str) without return types