code: def set_selection_strategy(self, strategy='spectral-oasis', nsel=1, neig=None):
          
          self._selection_strategy = selection_strategy(self, strategy, nsel, neig)
docs: Defines the column selection strategy
  
          Parameters
          ----------
          strategy : str
              One of the following strategies to select new columns:
              random : randomly choose from non-selected columns
              oasis : maximal approximation error in the diagonal of :math:`A`
              spectral-oasis : selects the nsel columns that are most distanced in the oASIS-error-scaled dominant eigenspace
          nsel : int
              number of columns to be selected in each round
          neig : int or None, optional, default None
              Number of eigenvalues to be optimized by the selection process.
              If None, use the whole available eigenspace