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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 trace_region(self, region_index):
 """Retrieves the properties of a trace region. Args: self (JLink):
 the ``JLink`` instance. region_index (int):
 the trace region index. Returns: An instance of ``JLinkTraceRegion`` describing the specified region. """

        cmd = enums.JLinkTraceCommand.GET_REGION_PROPS_EX
        region = structs.JLinkTraceRegion()
        region.RegionIndex = int(region_index)
        res = self._dll.JLINKARM_TRACE_Control(cmd, ctypes.byref(region))
        if (res == 1):
            raise errors.JLinkException('Failed to get trace region.')
        return region