Order of importance changes in set()

[Ysajid]

If set() is used in extract_key_phrases() function, then the order of importance changes while manipulating the set.

Result of running on same article 2 times:
{'account', 'personal information', 'surprise', 'political', 'scandal-plagued', 'privacy', 'network', 'possible', 'access', 'company', 'Instagram', 'survey', 'Spotify', 'Tinder', 'platform', 'turkey', 'security breach', 'Cambridge Analytica', 'database', 'Facebook', 'security scandal', 'innocuous', 'Research', 'percent', 'Friday'}

{'security breach', 'Instagram', 'percent', 'privacy', 'Research', 'network', 'political', 'Spotify', 'scandal-plagued', 'account', 'possible', 'Tinder', 'Facebook', 'platform', 'personal information', 'database', 'company', 'access', 'Friday', 'surprise', 'security scandal', 'survey', 'turkey', 'innocuous', 'Cambridge Analytica'}