new_contents: import unittest
  
  from stencil import Template
  
  
  class ExpressionTests(unittest.TestCase):
  
      def test_function(self):
          t = Template('Test {{f("abc")}}').render({"f": lambda x: x.title() })
  
          self.assertEqual(t, 'Test Abc')
  
      def test_function_argument(self):
          def double(a):
              return a * 2
  
          t = Template('Test {{double(double(1))}}').render({"double": double})
  
          self.assertEqual(t, 'Test 4')
  
subject: Add tests for latest fix