用于执行GA的DEAP包具有以下代码，可在此处http://aqibsaeed.github.io/2017-08-11-genetic-algorithm-for-optimizing-rnn/找到

population_size = 4
num_generations = 4
gene_length = 10

# As we are trying to minimize the RMSE score, that's why using -1.0.
# In case, when you want to maximize accuracy for instance, use 1.0
creator.create('FitnessMax', base.Fitness, weights = (-1.0,))
creator.create('Individual', list , fitness = creator.FitnessMax)

toolbox = base.Toolbox()
toolbox.register('binary', bernoulli.rvs, 0.5)
toolbox.register('individual', tools.initRepeat, creator.Individual, toolbox.binary,
n = gene_length)
toolbox.register('population', tools.initRepeat, list , toolbox.individual)

toolbox.register('mate', tools.cxOrdered)
toolbox.register('mutate', tools.mutShuffleIndexes, indpb = 0.6)
toolbox.register('select', tools.selRoulette)
toolbox.register('evaluate', train_evaluate)

population = toolbox.population(n = population_size)
r = algorithms.eaSimple(population, toolbox, cxpb = 0.4, mutpb = 0.1,
ngen = num_generations, verbose = False)

有人能告诉我“toolbox.register（'binary '，bernoulli.rvs，0.5）”行中的bernoulli是什么意思吗？