class_docstr: A registry of
  :class:`fiftyone.core.odm.document.MongoEngineBaseDocument` classes found
  when importing data from the database.
code: def __repr__(self):
      return repr(self._cache)
  
imports: from datetime import date, datetime
  import inspect
  import json
  import numbers
  import six
  import sys
  from bson import Binary, json_util, ObjectId, SON
  import numpy
  import pytz
  import fiftyone
  import fiftyone.core.fields
  import fiftyone.core.media
  import fiftyone.core.utils
label_desc: Use image node_id 2 for calling the DocumentRegistry obj's underlying member method code with example usage: obj.__repr__() and returns: repr