code: def _apply(self, ctx: ExtensionContext) -> AugmentedDict:
          
          def process(pattern: Pattern[str], _str: str) -> Any:
              _match = pattern.match(_str)
              if _match is None:
                  return _str  # pragma: no cover
              # We got a match
              # Group 0: Whole match; Group 1: Our placeholder;
              # Group 2: file path to external resource
              placeholder, external_path = _match.group(1), _match.group(2)
              with open(self.locator(
                      external_path,
                      cast(str, ctx.document) if Validator.is_file(document=ctx.document) else None
              )) as fhandle:
                  # Json does not support line breaks. We will have to mask them
                  content = fhandle.read()
              return _str.replace(placeholder, content)
  
          node_key, node_value = ctx.node
          _pattern = re.compile(self.__pattern__)
          return {node_key: process(_pattern, node_value)}
docs: Performs the actual loading of an external resource into the current model.
  
          Args:
              ctx: The processing context.
  
          Returns:
              Returns a dictionary that gets incorporated into the actual model.