code: def testBelowReferenceFrequency1(self):
      # Provide a single input peak below the reference frequency, so that the result is an empty pitch
      # salience function
      freq_speaks = [50]
      mag_speaks = [1]
      outputLength = 600
      expectedPitchSalience = zeros(outputLength)
      calculatedPitchSalience = PitchSalienceFunction()(
          freq_speaks, mag_speaks
      )
      self.assertEqualVector(
          calculatedPitchSalience, expectedPitchSalience
      )
  
imports: from essentia_test import *
  from numpy import *
label_desc: Use image node_id 13 for calling the TestPitchSalienceFunction obj's underlying member method code with example usage: obj.testBelowReferenceFrequency1() without return types