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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 _complete_cases(self, text, line, istart, iend):
 """Returns the completion list of possible test cases for the active unit test."""

        if text == "":
            return list(self.live.keys())
        else:
            return [c for c in self.live if c.startswith(text)]