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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_document(self, doc_uri):
 """Return a managed document if-present, else create one pointing at disk. See https://github.com/Microsoft/language-server-protocol/issues/177 """

        return self._docs.get(doc_uri) or self._create_document(doc_uri)