code: def load(self, coll):
          
          path = self.template_str.format(coll=coll)
          try:
              mtime = os.path.getmtime(path)
              obj = self.cache.get(path)
          except:
              return {}
  
          if not obj:
              return self.store_new(coll, path, mtime)
  
          cached_mtime, data = obj
          if mtime == cached_mtime == mtime:
              return obj
  
          return self.store_new(coll, path, mtime)
docs: Load and receive the metadata associated with a collection.
  
          If the metadata for the collection is not cached yet its metadata file is read in and stored.
          If the cache has seen the collection before the mtime of the metadata file is checked and if it is more recent
          than the cached time, the cache is updated and returned otherwise the cached version is returned.
  
          :param str coll: Name of a collection
          :return: The cached metadata for a collection
          :rtype: dict