code: def downgrade():
      """Unapply Add ``timetable_description`` column to DagModel for UI."""
      is_sqlite = bool(op.get_bind().dialect.name == "sqlite")
      if is_sqlite:
          op.execute("PRAGMA foreign_keys=off")
      with op.batch_alter_table("dag") as batch_op:
          batch_op.drop_column("timetable_description")
      if is_sqlite:
          op.execute("PRAGMA foreign_keys=on")
  
imports: from __future__ import annotations
  import sqlalchemy
  from alembic import op
label_desc: Use image node_id 2 for calling a global function with example usage: downgrade() without return types