code: def test_multivar_grad():
      op = SymPyCCode([xs, ys], xs**2 + ys**3)
      zt = op(xt, yt)
      dzdx, dzdy = theano.grad(zt, [xt, yt])
      assert dzdx.owner.op.expr == 2 * xs
      assert dzdy.owner.op.expr == 3 * ys**2
  
imports: from __future__ import absolute_import, print_function, division
  import theano
  from theano.scalar.basic_sympy import SymPyCCode
  from theano.scalar.basic import floats
  from nose.plugins.skip import SkipTest
label_desc: Use image node_id 3 for calling a global function with example usage: test_multivar_grad() without return types