code: def testLevel(self):
      ng = NoiseAdder(level=0)
      level_0 = ng(zeros(1000))
      self.assert_(all(abs(level_0) <= 1))
  
      ng.configure(level=-10)
      level_0_1 = ng(zeros(1000))
      k = db2lin(-10.0)
      self.assert_(all(abs(level_0_1) <= k))
  
      ng.configure(level=-30)
      level_0_3 = ng(ones(1000))
      k = db2lin(-30.0)
      self.assert_(all(abs(level_0_3 - ones(1000)) <= k))
  
imports: from essentia_test import *
label_desc: Use image node_id 2 for calling the TestNoiseAdder obj's underlying member method code with example usage: obj.testLevel() without return types