code: def downgrade():
      pass
  
file_path: superset/superset/migrations/versions/2022-03-02_09-20_b5a422d8e252_fix_query_and_saved_query_null_schema.py
imports: from alembic import op
  from sqlalchemy import Column, Integer, String
  from sqlalchemy.ext.declarative import declarative_base
  from superset import db
label_desc: Use image node_id 2 for calling a global function with example usage: downgrade() without return types