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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 feat(self,subset):
 """Obtain the feature class value of the specific subset. If a feature occurs multiple times, the values will be returned in a list. Example:: sense = word.annotation(folia.Sense) synset = sense.feat('synset') Returns: str or list """

        r = None
        for f in self:
            if isinstance(f, Feature) and f.subset == subset:
                if r: #support for multiclass features
                    if isinstance(r,list):
                        r.append(f.cls)
                    else:
                        r = [r, f.cls]
                else:
                    r = f.cls
        if r is None:
            raise NoSuchAnnotation
        else:
            return r