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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 getTreesFor(self, document, content_type):
 """Provides all XML documents for that content type @param document: a Document or subclass object @param content_type: a MIME content type @return: list of etree._ElementTree of that content type """


        # Relative path without potential leading path separator
        # otherwise os.path.join doesn't work
        for rel_path in self.overrides[content_type]:
            if rel_path[0] in ('/', '\\'):
                rel_path = rel_path[1:]
            file_path = os.path.join(document._cache_dir, rel_path)
            yield etree.parse(utils.xmlFile(file_path, 'rb'))
        return