text: # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  # http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  import alembic.command
  import click
  
  from warehouse.cli.db import alembic_lock, db
  
  
  @db.command()
  @click.argument("revision", required=True)
  @click.pass_obj
  def downgrade(config, revision, **kwargs):
      """
      Revert to a previous version.
      """
      with alembic_lock(
          config.registry["sqlalchemy.engine"], config.alembic_config()
      ) as alembic_config:
          alembic.command.downgrade(alembic_config, revision, **kwargs)
  