code: def test_rbf(self):
      code = """
  from math import exp
  def norm2_diff(x, y):
     def el(xi, yi):
         diff = xi - yi
         return diff * diff
     return sum(map(el, x, y))
  
  def rbf(ngamma, x, y):
     return exp(ngamma * norm2_diff(x,y))"""
      self.run_test(
          code,
          2.3,
          [1, 2, 3],
          [1.1, 1.2, 1.3],
          rbf=[float, List[int], List[float]],
      )
  
imports: from pythran.tests import TestEnv
  from pythran.typing import *
label_desc: Use image node_id 11 for calling the TestCopperhead obj's underlying member method code with example usage: obj.test_rbf() without return types