code: def downgrade():
      pass
  
file_path: superset/superset/migrations/versions/2019-11-06_15-23_78ee127d0d1d_reconvert_legacy_filters_into_adhoc.py
imports: import copy
  import json
  import logging
  from alembic import op
  from sqlalchemy import Column, Integer, Text
  from sqlalchemy.ext.declarative import declarative_base
  from superset import db
  from superset.utils.core import convert_legacy_filters_into_adhoc, split_adhoc_filters_into_base_filters
label_desc: Use image node_id 2 for calling a global function with example usage: downgrade() without return types