code: def test_DetectNonFittableDetector(self):
      detector = ThresholdDetector(low_threshold=0.2)
  
      # Check return types
      # Check if return TimeSeries is float when input is a series
      assert isinstance(detector.detect(self.test), TimeSeries)
  
      # Check if return type is Sequence when input is a Sequence of series
      assert isinstance(detector.detect([self.test]), Sequence)
  
      # Check if return TimeSeries is Sequence when input is a multivariate series
      assert isinstance(detector.detect(self.mts_test), TimeSeries)
  
      # Check if return type is Sequence when input is a multivariate series
      assert isinstance(detector.detect([self.mts_test]), Sequence)
  
      with pytest.raises(ValueError):
          # Input cannot be probabilistic
          detector.detect(self.probabilistic)
  
file_path: darts/darts/tests/ad/test_detectors.py
imports: from typing import Sequence
  import numpy
  import pytest
  from darts import TimeSeries
  from darts.ad.detectors.quantile_detector import QuantileDetector
  from darts.ad.detectors.threshold_detector import ThresholdDetector
label_desc: Use image node_id 1 for calling the TestADDetectors obj's underlying member method code with example usage: obj.test_DetectNonFittableDetector() without return types