docs: def thresh_from_spec(spec, labels, scores, **kwargs):
      r"""Find the threshold level that accomplishes the desired specificity"""
      cost_fun.verbose = kwargs.pop('verbose', cost_fun.verbose)
      cost_fun.target = spec
      return minimize(cost_fun,
                      x0=[.5],
                      args=(labels, scores),
                      method='SLSQP',
                      constraints=({'type': 'ineq',
                                    'fun': lambda x: np.array([x[0]]),
                                    'jac': lambda x: np.array([1.])},
                                   ),
                      **kwargs
                      )