code: def init_versioning(self, app, database, versioning_manager=None):
          
          try:
              pkg_resources.get_distribution('sqlalchemy_continuum')
          except pkg_resources.DistributionNotFound:  # pragma: no cover
              default_versioning = False
          else:
              default_versioning = True
  
          app.config.setdefault('DB_VERSIONING', default_versioning)
  
          if not app.config['DB_VERSIONING']:
              return
  
          if not default_versioning:  # pragma: no cover
              raise RuntimeError(
                  'Please install extra versioning support first by running '
                  'pip install invenio-db[versioning].'
              )
  
          # Now we can import SQLAlchemy-Continuum.
          from sqlalchemy_continuum import make_versioned
          from sqlalchemy_continuum import versioning_manager as default_vm
          from sqlalchemy_continuum.plugins import FlaskPlugin
  
          # Try to guess user model class:
          if 'DB_VERSIONING_USER_MODEL' not in app.config:  # pragma: no cover
              try:
                  pkg_resources.get_distribution('invenio_accounts')
              except pkg_resources.DistributionNotFound:
                  user_cls = None
              else:
                  user_cls = 'User'
          else:
              user_cls = app.config.get('DB_VERSIONING_USER_MODEL')
  
          plugins = [FlaskPlugin()] if user_cls else []
  
          # Call make_versioned() before your models are defined.
          self.versioning_manager = versioning_manager or default_vm
          make_versioned(
              user_cls=user_cls,
              manager=self.versioning_manager,
              plugins=plugins,
          )
  
          # Register models that have been loaded beforehand.
          builder = self.versioning_manager.builder
  
          for tbl in database.metadata.tables.values():
              builder.instrument_versioned_classes(
                  database.mapper, get_class_by_table(database.Model, tbl)
              )
docs: Initialize the versioning support using SQLAlchemy-Continuum.