code: def get_last_invalidation(*tables_or_models, **kwargs):
      
      # TODO: Replace with positional arguments when we drop Python 2 support.
      cache_alias = kwargs.pop('cache_alias', None)
      db_alias = kwargs.pop('db_alias', None)
      for k in kwargs:
          raise TypeError("get_last_invalidation() got an unexpected "
                          "keyword argument '%s'" % k)
  
      last_invalidation = 0.0
      for cache_alias, db_alias, tables in _cache_db_tables_iterator(
              list(_get_tables(tables_or_models)), cache_alias, db_alias):
          get_table_cache_key = cachalot_settings.CACHALOT_TABLE_KEYGEN
          table_cache_keys = [get_table_cache_key(db_alias, t) for t in tables]
          invalidations = cachalot_caches.get_cache(
              cache_alias, db_alias).get_many(table_cache_keys).values()
          if invalidations:
              current_last_invalidation = max(invalidations)
              if current_last_invalidation > last_invalidation:
                  last_invalidation = current_last_invalidation
      return last_invalidation
docs: Returns the timestamp of the most recent invalidation of the given
      ``tables_or_models``.  If ``tables_or_models`` is not specified,
      all tables found in the database (including those outside Django) are used.
  
      If ``cache_alias`` is specified, it only fetches invalidations
      in this cache, otherwise invalidations in all caches are fetched.
  
      If ``db_alias`` is specified, it only fetches invalidations
      for this database, otherwise invalidations for all databases are fetched.
  
      :arg tables_or_models: SQL tables names, models or models lookups
                             (or a combination)
      :type tables_or_models: tuple of strings or models
      :arg cache_alias: Alias from the Django ``CACHES`` setting
      :type cache_alias: string or NoneType
      :arg db_alias: Alias from the Django ``DATABASES`` setting
      :type db_alias: string or NoneType
      :returns: The timestamp of the most recent invalidation
      :rtype: float