code: def function(x):
      """a simple model function
      f = (x1*x2*x3)**(1/3)
  
      Input:
        - x -- 1-d array of coefficients [x1,x2,x3]
  
      Output:
        - f -- function result
      """
      return (x[0] * x[1] * x[2]) ** (1.0 / 3.0)
  
label_desc: Use image node_id 1 for calling a global function with example usage: function(x) and returns: unknown