Incorrect plural of quiz (gives quizs not quizzes)

[tringham]

In [2]: pattern.en.pluralize("quiz") Out[2]: 'quizs'

Should be quizzes - as the singularize method does know

In [3]: pattern.en.singularize("quizzes") Out[3]: 'quiz'

[dsaw]

The same issue is happening with the word "bus".

>>> pluralize('bus')
buss
>>> singularize('buses')
bus