code: def currency(x, pos):
      """The two arguments are the value and tick position"""
      if x >= 1e6:
          s = f"${x*1e-6:1.1f}M"
      else:
          s = f"${x*1e-3:1.0f}K"
      return s
  
label_desc: Use image node_id 1 for calling a global function with example usage: currency(x, pos) and returns: s