class_docstr: Upload file(s) from browser to Python kernel as bytes
class_docstr_tok: ["Upload","file","(","s",")","from","browser","to","Python","kernel","as","bytes"]
docstr: counter increment triggers the update of trait value
docstr_tok: ["counter","increment","triggers","the","update","of","trait","value"]
code: def on_incr_counter(self, change):
      """
      counter increment triggers the update of trait value
      """
      res = {}
      msg = "Error: length of metadata and data must be equal"
      assert len(self.metadata) == len(self.data), msg
      for metadata, content in zip(self.metadata, self.data):
          name = metadata["name"]
          res[name] = {"metadata": metadata, "content": content}
      self.set_trait("value", res)
  
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 the FileUpload obj's underlying member method code with example usage: obj.on_incr_counter(change) without return types