What is the isEmpty() and isNotEmpty() methods in Collect.js?

isEmpty() : The isEmpty method returns true if the collection is empty; otherwise, false is returned:
collect().isEmpty();
// true

collect([]).isEmpty();
// true

collect({}).isEmpty();
// true
isNotEmpty() : The isNotEmpty() method returns true if the collection is not empty; otherwise, false is returned:
collect([1, 2, 3]).isNotEmpty();
//  true

collect().isNotEmpty();
// false

collect([]).isNotEmpty();
// false

collect({}).isNotEmpty();
// false