def next_orthant_to_cover(model_layer_dict):
    not_covered = [(neuron_group, orthant) for ((neuron_group, orthant), v) in model_layer_dict.items() if (not v)]
    if not_covered:
        (neuron_group, orthant) = random.choice(not_covered)
    else:
        (neuron_group, orthant) = random.choice(model_layer_dict.keys())
    return (neuron_group, orthant)
def next_orthant_to_cover(model_layer_dict):
    not_covered = [(neuron_group, orthant) for ((neuron_group, orthant), v) in model_layer_dict.items() if (not v)]
    if not_covered:
        (neuron_group, orthant) = random.choice(not_covered)
    else:
        (neuron_group, orthant) = random.choice(model_layer_dict.keys())
    return (neuron_group, orthant)