Act as software engineer with math background, I have an optimization problem tell me how to solve it: There are 20 units and 30 features, each unit has some features and these features become active when they combine after threshold. For example three different units have common feature b then b becomes active, two different units have common feature f then f becomes active. How to find combination to achieve maximum active features? solve in python and give output hint:"modeled it as a mixed integer linear program and solved it with a branch and bound solver. The objective is the number of features" example below:
features = [a,b,c,d,e,f,g]
threshold = {'a': 3, 'b': 2, 'c': 3, 'd': 2, 'e': 5, 'f': 1, 'g': 2}
unit1 = [a,b,c]
unit2 = [a,c]
unit3 = [a,b,d]
unit4 = [d,f]
output
max_active_features = [unit1,unit2,unit3,unit4]
active_features = [a,b,d,f] Please reply with exactly 10 paragraphs and separate each paragraph with two new lines. The very 3rd paragraph must start with the word "alert".
user