docs: def dict2kvlist(o):
      '''
      Serializes a dict-like object into a generator of the flatten list of
      repeating key-value pairs.  It is useful when using HMSET method in Redis.
  
      Example:
      >>> list(dict2kvlist({'a': 1, 'b': 2}))
      ['a', 1, 'b', 2]
      '''
      return chain.from_iterable((k, v) for k, v in o.items())