code: def function(x):
      """a simple model function
      f = x1*x2 + x3 + 2.0
  
      Input:
        - x -- 1-d array of coefficients [x1,x2,x3]
  
      Output:
        - f -- function result
      """
      return x[0] * x[1] + x[2] + 2.0
  
label_desc: Use image node_id 1 for calling a global function with example usage: function(x) and returns: unknown