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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 serve_post(self, path, postmap, **params):
 """ Find a POST callback for the given HTTP path, call it and return the results. The callback is called with the path used to match it, a dict of vars from the POST body and params which include the BaseHTTPRequestHandler instance. The callback must return a tuple: (code, content, content_type) If multiple registrations match the path, the one with the longest matching text will be used. Matches are always anchored at the start of the path. None is returned if no registered callback is willing to handle a path. """

        matched = self._match_path(path, self.post_registrations)
        if matched is None:                                                                     # pragma: no cover
            return None
        else:
            return matched(path, postmap, **params)