code: def _cost_method(self, *args, **kwargs):
          
  
          if 'verbose' in kwargs and kwargs['verbose']:
              print(' - Min (X):', np.min(args[0]))
  
          return 0.0
docs: Calculate positivity component of the cost
  
          This method returns 0 as the posivituty does not contribute to the
          cost.
  
          Returns
          -------
          float zero