code: def export_json(obj, file_name):
      
      def callback(data):
          return json.dumps(data, indent=4)
  
      # Export data
      exported_data = exch.export_dict_str(obj=obj, callback=callback)
  
      # Write to file
      return exch.write_file(file_name, exported_data)
docs: Exports curves and surfaces in JSON format.
  
      JSON format is also used by the `geomdl command-line application <https://github.com/orbingol/geomdl-cli>`_
      as a way to input shape data from the command line.
  
      :param obj: input geometry
      :type obj: abstract.SplineGeometry, multi.AbstractContainer
      :param file_name: name of the output file
      :type file_name: str
      :raises GeomdlException: an error occurred writing the file