docs: def generator_by_digest(family, digest_size):
  		""" Return generator by hash generator family name and digest size
  
  		:param family: name of hash-generator family
  
  		:return: WHashGeneratorProto class
  		"""
  		for generator_name in WHash.available_generators(family=family):
  			generator = WHash.generator(generator_name)
  			if generator.generator_digest_size() == digest_size:
  				return generator
  		raise ValueError('Hash generator is not available')