code: def upgrade():
      bind = op.get_bind()
      session = db.Session(bind=bind)
  
      slices = (
          session.query(Slice)
          .filter(Slice.viz_type.like(CHART_TYPE))
          .all()
      )
      for slc in slices:
          try:
              params = json.loads(slc.params)
              stack = params.get("stack", None)
              if stack:
                  params["stack"] = "Stack"
              else:
                  params["stack"] = None
              slc.params = json.dumps(params, sort_keys=True)
          except Exception as e:
              print(e)
              print(f"Parsing params for slice {slc.id} failed.")
              pass
  
      session.commit()
      session.close()
  
file_path: superset/superset/migrations/versions/2023-03-17_13-24_b5ea9d343307_bar_chart_stack_options.py
imports: import json
  import sqlalchemy
  from alembic import op
  from sqlalchemy import and_, Column, Integer, String, Text
  from sqlalchemy.ext.declarative import declarative_base
  from superset import db
label_desc: Use image node_id 1 for calling a global function with example usage: upgrade() without return types