code: def downgrade() -> None:
      # ### commands auto generated by Alembic - please adjust! ###
      with op.batch_alter_table("codes", schema=None) as batch_op:
          batch_op.alter_column(
              "blob", existing_type=sa.BLOB(), nullable=False
          )
  
imports: import sqlalchemy
  import sqlalchemy_utils
  from alembic import op
label_desc: Use image node_id 2 for calling a global function with example usage: downgrade() without return types