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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 caption_mentions(self) -> List[str]: """List of all lowercased profiles that are mentioned in the Post's caption, without preceeding @."""

        if not self.caption:
            return []
        # This regular expression is from jStassen, adjusted to use Python's \w to support Unicode
        # http://blog.jstassen.com/2016/03/code-regex-for-instagram-username-and-hashtags/
        mention_regex = re.compile(r"(?:@)(\w(?:(?:\w|(?:\.(?!\.))){0,28}(?:\w))?)")
        return re.findall(mention_regex, self.caption.lower())