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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 get_top_tags(self, limit=None, cacheable=True):
 """Returns the most used tags as a sequence of TopItem objects."""


        # Last.fm has no "limit" parameter for tag.getTopTags
        # so we need to get all (250) and then limit locally
        doc = _Request(self, "tag.getTopTags").execute(cacheable)

        seq = []
        for node in doc.getElementsByTagName("tag"):
            if limit and len(seq) >= limit:
                break
            tag = Tag(_extract(node, "name"), self)
            weight = _number(_extract(node, "count"))
            seq.append(TopItem(tag, weight))

        return seq