code: def set_default_viewers(self, doctypes=None):
      if not doctypes:
          doctypes = self.DOCTYPES
      for doctype in doctypes:
          self.set_default_viewer(doctype)
      return self
  
file_path: jupytext/src/jupytext_config/labconfig.py
imports: import json
  import logging
  from pathlib import Path
label_desc: Use image node_id 5 for calling the LabConfig obj's underlying member method code with example usage: obj.set_default_viewers(doctypes) and returns: self