code: def _filter_none(original: dict) -> dict:
      def _filter_val(value):
          if isinstance(value, dict):
              return _filter_none(value)
          else:
              return value
  
      return {
          k: _filter_val(v)
          for k, v in original.items()
          if v is not None
      }
  
file_path: lets-plot/python-package/lets_plot/plot/theme_.py
imports: from .core import FeatureSpec
label_desc: Use image node_id 2 for calling a global function with example usage: _filter_none(original) and returns: unknown, _filter_none, value