class_docstr: Traitlet for validating a single (Widget, 'trait_name') pair
class_docstr_tok: ["Traitlet","for","validating","a","single","(","Widget",",","'trait_name","'",")","pair"]
code: def __init__(self, **kwargs):
      super().__init__(Instance(Widget), Unicode(), **kwargs)
      if "default_value" not in kwargs and not kwargs.get(
          "allow_none", False
      ):
          # This is to keep consistent behavior for spec generation between traitlets 4 and 5
          # Having a default empty container is explicitly not allowed in traitlets 5 when
          # there are traits specified (as the default value will be invalid), but we do it
          # anyway as there is no empty "default" that makes sense.
          self.default_args = ()
  
file_path: catboost/contrib/python/ipywidgets/py3/ipywidgets/widgets/widget_link.py
imports: from .widget import Widget, register, widget_serialization
  from .widget_core import CoreWidget
  from traitlets import Unicode, Tuple, Instance, TraitError
label_desc: Use image node_id 1 to create a new WidgetTraitTuple object from inherited base classes: Tuple with example: obj = WidgetTraitTuple()