import Orange

data = Orange.data.Table("iris")
learner = Orange.classification.CN2UnorderedLearner()

# consider up to 10 solution streams at one time
learner.rule_finder.search_algorithm.beam_width = 10

# continuous value space is constrained to reduce computation time
learner.rule_finder.search_strategy.constrain_continuous = True

# found rules must cover at least 15 examples
learner.rule_finder.general_validator.min_covered_examples = 15

# found rules may combine at most 2 selectors (conditions)
learner.rule_finder.general_validator.max_rule_length = 2

classifier = learner(data)