python from rainbow.flow import Flow def filter_age(user): return user.age > 18 flow = Flow.from_list(users) filtered_flow = flow.filter(filter_age) python from rainbow.flow import Flow def map_age_to_str(user): return str(user.age) flow = Flow.from_list(users) mapped_flow = flow.map(map_age_to_str) python from rainbow.flow import Flow def reduce_age(acc, user): return acc + user.age flow = Flow.from_list(users) average_age = flow.reduce(reduce_age, initial=0) / flow.count() python from rainbow.flow import Flow flow = Flow.from_list(users) sorted_flow = flow.sort(key=lambda user: user.age)