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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 _load_tcmps_lib():
 """ Load global singleton of tcmps lib handler. This function is used not used at the top level, so that the shared library is loaded lazily only when needed. """

    global _g_TCMPS_LIB
    if _g_TCMPS_LIB is None:
        # This library requires macOS 10.14 or above
        if _mac_ver() < (10, 14):
            return None

        # The symbols defined in libtcmps are now exposed directly by
        # libunity_shared. Eventually the object_detector and
        # activity_classifier toolkits will use the same Python/C++ bridge as
        # the other toolkits, and this usage of ctypes will go away.
        file_dir = _os.path.dirname(__file__)
        lib_path = _os.path.abspath(_os.path.join(file_dir, _os.pardir, 'libunity_shared.dylib'))
        try:
            _g_TCMPS_LIB = _ctypes.CDLL(lib_path, _ctypes.RTLD_LOCAL)
        except OSError:
            pass
    return _g_TCMPS_LIB