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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 indexableText(self, include_properties=True):
 """Words found in the various texts of the document. :param include_properties: Adds words from properties :return: Space separated words of the document. """

        text = set()
        for extractor in self._text_extractors:
            if extractor.content_type in self.content_types.overrides:
                for tree in self.content_types.getTreesFor(self, extractor.content_type):
                    words = extractor.indexableText(tree)
                    text |= words

        if include_properties:
            for prop_value in self.allProperties.values():
                if prop_value is not None:
                    text.add(prop_value)
        return u' '.join([word for word in text])