요즘은 잘 안묻는 유명한 코딩 인터뷰 문제. An array is given as an iterator with .has_next() and .next() methods. E.g. # iterating the array iterator while data.has_next(): print(data.next()) where .has_next() returns True if there is a next element to read, otherwise False, and .next() yields the next array element if .has_next() is true. Write a function that randomly and fairly samples k elements from this array given as an iterator.