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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 finditer(self, expr):
 """Return an iterator over all matches in `expr` Iterate over all :class:`MatchDict` results of matches for any matching (sub-)expressions in `expr`. The order of the matches conforms to the equivalent matched expressions returned by :meth:`findall`. """

        try:
            for arg in expr.args:
                for m in self.finditer(arg):
                    yield m
            for arg in expr.kwargs.values():
                for m in self.finditer(arg):
                    yield m
        except AttributeError:
            pass
        m = self.match(expr)
        if m:
            yield m