code: def upload(sample_rate=DEFAULT_SAMPLE_RATE, normalize_db=None):
      """Load a collection of audio files (.wav, .mp3) from disk into colab.
  
      Args:
        sample_rate: Resample recorded audio to this sample rate.
        normalize_db: Normalize the audio to this many decibels. Set to None to skip
          normalization step.
  
      Returns:
        An tuple of lists, (filenames, numpy_arrays).
      """
      audio_files = files.upload()
      fnames = list(audio_files.keys())
      audio = []
      for fname in fnames:
          file_audio = audio_bytes_to_np(
              audio_files[fname],
              sample_rate=sample_rate,
              normalize_db=normalize_db,
          )
          audio.append(file_audio)
      return fnames, audio
  
file_path: ddsp/ddsp/colab/colab_utils.py
imports: import base64
  import io
  import pickle
  import ddsp
  import ddsp.training
  from google.colab import files
  from google.colab import output
  from IPython import display
  import note_seq
  import numpy
  from scipy.io import wavfile
  import tensorflow.compat.v2
label_desc: Use image node_id 4 for calling a global function with example usage: upload(sample_rate, normalize_db) and returns: fnames,  audio