code: def test_sixhumpcamel(self):
      self.assertEqual(
          sixhumpcamel((-0.08984201368301331, 0.7126564032704135)),
          -1.0316284534898774,
          msg="sixhumpcamel failed for 2 arguments ",
      )
  
file_path: scikit-opt/tests/test_demo_func.py
imports: import unittest
  from sko.demo_func import ackley, cigar, function_for_TSP, rastrigrin, rosenbrock, sixhumpcamel, sphere, schaffer, zakharov, shubert, griewank, rastrigrin, rosenbrock, sixhumpcamel, zakharov, ackley, cigar
label_desc: Use image node_id 11 for calling the TestDemoFunc obj's underlying member method code with example usage: obj.test_sixhumpcamel() without return types