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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 header_id_from_text(self, text, prefix, n):
 """Generate a header id attribute value from the given header HTML content. This is only called if the "header-ids" extra is enabled. Subclasses may override this for different header ids. @param text {str} The text of the header tag @param prefix {str} The requested prefix for header ids. This is the value of the "header-ids" extra key, if any. Otherwise, None. @param n {int} The <hN> tag number, i.e. `1` for an <h1> tag. @returns {str} The value for the header tag's "id" attribute. Return None to not have an id attribute and to exclude this header from the TOC (if the "toc" extra is specified). """

        header_id = _slugify(text)
        if prefix and isinstance(prefix, base_string_type):
            header_id = prefix + '-' + header_id
        if header_id in self._count_from_header_id:
            self._count_from_header_id[header_id] += 1
            header_id += '-%s' % self._count_from_header_id[header_id]
        else:
            self._count_from_header_id[header_id] = 1
        return header_id