Given a list of matching/equivalent song pairs and a list of unique songs, create unique sets of equivalent songs.\n\n**Example 1:**\n```\nInput: \nmatching pairs: [[1, 2], [2, 3], [5, 6], [4, 6], [2, 7], [3, 8], [9, 10]]\nunique songs: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]\nOutput: [[1, 2, 3, 7, 8], [4, 5, 6], [9, 10]]\n```\nNote that transitivity should be considered.\n

Given a list of matching/equivalent song pairs and a list of unique songs, create unique sets of equivalent songs.\n\nExample 1:\n\nInput: \nmatching pairs: [[1