python - 如何對清單中的清單進行頻率統計？
例如此列表：
[['software', 'foundation'], ['of', 'the'], ['the', 'python'], ['software', 'foundation'],['of', 'the'], ['software', 'foundation']]
# 进行频率统计，例如输出结果为：
("['software','foundation']", 3), ("['of', 'the']", 2), ("['the', 'python']", 1)
