code: def _fix_tbit_dtype(self, array, colnums):
          
          descr = array.dtype.descr
          for i, colnum in enumerate(colnums):
              npy_type, isvar, istbit = self._get_tbl_numpy_dtype(colnum)
              if (istbit):
                  coldescr = list(descr[i])
                  coldescr[1] = '?'
                  descr[i] = tuple(coldescr)
  
          return array.view(descr)
docs: If necessary, patch up the TBIT to convert to bool array
  
          parameters
          ----------
          array: record array
          colnums: column numbers for lookup