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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_css_classes(self, ttype):
 """Return the css classes of this token type prefixed with the classprefix option."""

        cls = self._get_css_class(ttype)
        while ttype not in STANDARD_TYPES:
            ttype = ttype.parent
            cls = self._get_css_class(ttype) + ' ' + cls
        return cls