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