code: def merge(config, revisions, **kwargs):
      
      with alembic_lock(
          config.registry["sqlalchemy.engine"], config.alembic_config()
      ) as alembic_config:
          alembic.command.merge(alembic_config, revisions, **kwargs)
docs: Merge one or more revisions.
  
      Takes one or more revisions or "heads" for all heads and merges them into
      a single revision.