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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 tags(self):
 """Returns a `set` of unique tags contained in `raw_content`."""

        if not self.raw_content:
            return set()
        return {word.strip("#").lower() for word in self.raw_content.split() if word.startswith("#") and len(word) > 1}