code: def testFile(self):
      filename = join(
          testdata.audio_dir,
          "generated",
          "synthesised",
          "sin_pattern_decreasing.wav",
      )
      audioLeft = MonoLoader(
          filename=filename, downmix="left", sampleRate=44100
      )()
      envelope = Envelope(
          sampleRate=44100, attackTime=5, releaseTime=100
      )(audioLeft)
      for x in envelope:
          self.assertValidNumber(x)
  
file_path: essentia/test/src/unittests/standard/test_envelope.py
imports: from essentia_test import *
  import numpy
label_desc: Use image node_id 1 for calling the TestEnvelope obj's underlying member method code with example usage: obj.testFile() without return types