class_docstr: SQLite3 TaskRecord backend.
docstr: create an empty record
docstr_tok: ["create","an","empty","record"]
code: def _defaults(self, keys=None):
      """create an empty record"""
      d = {}
      keys = self._keys if keys is None else keys
      for key in keys:
          d[key] = None
      return d
  
imports: import json
  import os
  from datetime import datetime
  from dateutil.parser import parse
  from tornado import ioloop
  from traitlets import Dict, Instance, List, Unicode
  from ..util import ensure_timezone, extract_dates
  from .dictdb import BaseDB
label_desc: Use image node_id 3 for calling the SQLiteDB obj's underlying member method code with example usage: obj._defaults(keys) and returns: d