code: def content_from_json(value, widget):
      """
      deserialize file content
      """
      from_json = bytes_serialization["from_json"]
      output = [from_json(e, None) for e in value]
      return output
  
file_path: catboost/contrib/python/ipywidgets/py2/ipywidgets/widgets/widget_upload.py
imports: from traitlets import observe, default, Unicode, Dict, List, Int, Bool, Bytes, CaselessStrEnum
  from .widget_description import DescriptionWidget
  from .valuewidget import ValueWidget
  from .widget_core import CoreWidget
  from .widget_button import ButtonStyle
  from .widget import register, widget_serialization
  from .trait_types import bytes_serialization, InstanceDict
label_desc: Use image node_id 1 for calling a global function with example usage: content_from_json(value, widget) and returns: output