code: def get_installed_packs(cache=None):
          
          try:
              cache = cache or cmsis_pack_manager.Cache(True, True)
              results = []
              # packs_for_devices() returns only unique packs.
              for pack in cache.packs_for_devices(cache.index.values()):
                  pack_path = os.path.join(cache.data_path, pack.get_pack_name())
                  if os.path.isfile(pack_path):
                      results.append(pack)
              return results
          except FileNotFoundError:
              # cmsis-pack-manage can raise this exception if the cache is empty.
              return []
docs: ! @brief Return a list containing CmsisPackRef objects for all installed packs.