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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 mps_device_name():
 """ Returns name of MPS device that will be used, else None. """

    lib = _load_tcmps_lib()
    if lib is None:
        return None

    n = 256
    c_name = (_ctypes.c_char * n)()
    ret = lib.TCMPSMetalDeviceName(_ctypes.byref(c_name), _ctypes.c_int32(n))
    if ret == 0:
        return _decode_bytes_to_native_string(c_name.value)
    else:
        return None