>>> from clotheshop import update_stock

>>> d = {('Pan85', 'XS','black'):100,('Pan85','S','black'):300,
... ('Pan85','XS','blue'):6,('Pan87','S','blue'):5,
... ('Pan87','L','blue'):12,('Pan85','M','white'):6,
... ('Pan85','L','white'):5,('Cam23','XL','white'):12}
>>> lsales = [['Pan87','S','blue',3],['Cam23','XL','white',9],
... ['Pan87','L','blue',1]]
>>> lrstock = [['Pan87','L','blue',5],['Cam23','S','blue',5]]
>>> update_stock(d,lsales,lrstock)
>>> if d != {('Pan85', 'XS','black'):100,('Pan85','S','black'):300,
... ('Pan85','XS','blue'):6,('Pan87','S','blue'):2,
... ('Pan87','L','blue'):16,('Pan85','M','white'):6,
... ('Pan85','L','white'):5,('Cam23','XL','white'):3,
... ('Cam23','S','blue'):5}:
...    print(d)