code: def join(chord_root, quality='', extensions=None, bass=''):
      r
      chord_label = chord_root
      if quality or extensions:
          chord_label += ":%s" % quality
      if extensions:
          chord_label += "(%s)" % ",".join(extensions)
      if bass and bass != '1':
          chord_label += "/%s" % bass
      validate_chord_label(chord_label)
      return chord_label
docs: r"""Join the parts of a chord into a complete chord label.
  
      Parameters
      ----------
      chord_root : str
          Root pitch class of the chord, e.g. 'C', 'Eb'
      quality : str
          Quality of the chord, e.g. 'maj', 'hdim7'
          (Default value = '')
      extensions : list
          Any added or absent scaled degrees for this chord, e.g. ['4', '\*3']
          (Default value = None)
      bass : str
          Scale degree of the bass note, e.g. '5'.
          (Default value = '')
  
      Returns
      -------
      chord_label : str
          A complete chord label.