code: def generate_waveforms(length, frequencies):
      """
      generate sinewaves with given frequencies,
      add Hann envelope and store in channel-last layout
      """
      n = int(math.ceil(length))
      X = np.arange(n, dtype=np.float32)
  
      def window(x):
          x = 2 * x / length - 1
          np.clip(x, -1, 1, out=x)
          return 0.5 * (1 + np.cos(x * math.pi))
  
      wave = np.sin(
          X[:, np.newaxis] * (np.array(frequencies) * (2 * math.pi))
      )
      return wave * window(X)[:, np.newaxis]
  
imports: import numpy
  import math
  import librosa
label_desc: Use image node_id 1 for calling a global function with example usage: generate_waveforms(length, frequencies) and returns: unknown, unknown