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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 fetch_digests(self, package_name: str, package_version: str) -> dict: """Fetch digests for the given package in specified version from the given package index."""

        report = {}

        for source in self._sources:
            try:
                report[source.url] = source.get_package_hashes(package_name, package_version)
            except NotFound as exc:
                _LOGGER.debug(
                    f"Package {package_name} in version {package_version} not "
                    f"found on index {source.name}: {str(exc)}"
                )

        return report