code: def cb_multilayer(ctx, param, value):
      """
      Transform layer options from strings ("1:a,1:b", "2:a,2:c,2:z") to
      {
      '1': ['a', 'b'],
      '2': ['a', 'c', 'z']
      }
      """
      out = defaultdict(list)
      for raw in value:
          for v in raw.split(","):
              ds, name = v.split(":")
              out[ds].append(name)
      return out
  
imports: from collections import defaultdict
  import click
label_desc: Use image node_id 2 for calling a global function with example usage: cb_multilayer(ctx, param, value) and returns: out