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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _apply(self, ctx: ExtensionContext) -> Any: """ Loads a yaml fragment from an external file. Args: ctx: The processing context. Returns: The external resource as a python dictionary. The fragment is already send through the processor as well. """

        _, external_path = ctx.node
        return ctx.mentor.load_yaml(self.locator(
            external_path,
            cast(str, ctx.document) if Validator.is_file(document=ctx.document) else None
        ))