code: def argument_is_proportion(argname):
      @decorator
      def argument_is_proportion(func, *args, **kwargs):
          """Validate that an argument is a proportion [0, 1.0]"""
          arg_maps = map_parameters_in_fn_call(args, kwargs, func)
          value = arg_maps.get(argname)
  
          # Validate value, but only if has a value
          if (not (0 <= value <= 1.0)) and value is not None:
              raise ValueError(
                  "{argname} must be between 0 and 1.0".format(
                      argname=argname
                  )
              )
          return func(*args, **kwargs)
  
      return argument_is_proportion
  
label_desc: Use image node_id 1 for calling a global function with example usage: argument_is_proportion(argname) and returns: argument_is_proportion, func