code: def initialize_communities_bucket():
      
      bucket_id = UUID(current_app.config['COMMUNITIES_BUCKET_UUID'])
  
      if Bucket.query.get(bucket_id):
          raise FilesException("Bucket with UUID {} already exists.".format(
              bucket_id))
      else:
          storage_class = current_app.config['FILES_REST_DEFAULT_STORAGE_CLASS']
          location = Location.get_default()
          bucket = Bucket(id=bucket_id,
                          location=location,
                          default_storage_class=storage_class)
          db.session.add(bucket)
          db.session.commit()
docs: Initialize the communities file bucket.
  
      :raises: `invenio_files_rest.errors.FilesException`