code: def test_CondVariable():
      expr = C("CAdd", (1, 2))
      x = Variable("x")
      y = CondVariable("y", lambda a: a % 2 == 0)
      z = CondVariable("z", lambda a: a > 3)
      pattern = C("CAdd", (x, y))
      assert list(unify(expr, pattern, {})) == [{x: 1, y: 2}]
  
      z = CondVariable("z", lambda a: a > 3)
      pattern = C("CAdd", (z, y))
  
      assert list(unify(expr, pattern, {})) == []
  
file_path: sympy/sympy/unify/tests/test_unify.py
imports: from sympy.unify.core import Compound, Variable, CondVariable, allcombinations
  from sympy.unify import core
label_desc: Use image node_id 12 for calling a global function with example usage: test_CondVariable() without return types