print(invertdict(canonical))
{'ARS': ('ARS', 'Arsenal'), 'MNU': ('ManUtd', 'Manchester United', 'MNU')}
print(invertdict(invertdict(canonical)))
{'MNU': ('MNU',), 'Manchester United': ('MNU',), 'ARS': ('ARS',), 'Arsenal':
    ('ARS',), 'ManUtd': ('MNU',)}
Finding equality between different strings that should be equal