code: def downgrade():
      """Unapply Rename ``concurrency`` column in ``dag`` table to`` max_active_tasks``"""
      with op.batch_alter_table("dag") as batch_op:
          batch_op.alter_column(
              "max_active_tasks",
              new_column_name="concurrency",
              type_=sa.Integer(),
              nullable=False,
          )
  
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