code: def _loadlib(lib='standard'):
      
      global _LIB
      if _LIB is not None:
          warnings.warn('rabit.int call was ignored because it has'\
                            ' already been initialized', level=2)
          return
      if lib == 'standard':
          _LIB = ctypes.cdll.LoadLibrary(WRAPPER_PATH % '')
      elif lib == 'mock':
          _LIB = ctypes.cdll.LoadLibrary(WRAPPER_PATH % '_mock')
      elif lib == 'mpi':
          _LIB = ctypes.cdll.LoadLibrary(WRAPPER_PATH % '_mpi')
      else:
          raise Exception('unknown rabit lib %s, can be standard, mock, mpi' % lib)
      _LIB.RabitGetRank.restype = ctypes.c_int
      _LIB.RabitGetWorldSize.restype = ctypes.c_int
      _LIB.RabitVersionNumber.restype = ctypes.c_int
docs: Load rabit library.