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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def fonts(self):
 """Generator yielding all fonts of this typeface Yields: Font: the next font in this typeface """

        for width in (w for w in FontWidth if w in self):
            for slant in (s for s in FontSlant if s in self[width]):
                for weight in (w for w in FontWeight
                               if w in self[width][slant]):
                    yield self[width][slant][weight]