code: def get_keyboard_edges(firstnote=21, lastnote=108):
      octaves = 10
  
      # build template of white notes
      scalew = 12 / 7.0
      xw_temp = [i * scalew for i in range(0, 7)]
      # build template of black notes
      scaleb = 6 / 7.0
      xb_temp = [i * scaleb for i in [1, 3, 7, 9, 11]]
  
      xb, xw = [], []
      for octave in range(octaves - 1):
          for i in xb_temp:
              curnote = i + 12 * octave
              if curnote > firstnote - 1 and curnote < lastnote + 1:
                  xb = xb + [curnote]
      for octave in range(octaves - 1):
          for i in xw_temp:
              curnote = i + 12 * octave
              if curnote > firstnote - 1 and curnote < lastnote + 1:
                  xw = xw + [curnote]
  
      return xb, xw, 2 / 3.0 * scaleb, 1 / 2.0 * scalew
  
label_desc: Use image node_id 1 for calling a global function with example usage: get_keyboard_edges(firstnote, lastnote) and returns: xb,  xw,  unknown,  unknown