fix another keyword problem

jedi/parsing.py

@@ -659,6 +659,7 @@ class Parser(object):
                 continue
             elif tok == 'assert':
                 stmt, tok = self._parse_statement()
+                if stmt is not None:
                     stmt.parent = use_as_parent_scope
                 self._scope.asserts.append(stmt)
             # default

test/test_regression.py

@@ -326,6 +326,9 @@ class TestRegression(TestBase):
         assert len(defs) == 0
         completions = self.completions("import", (1,1))
         assert len(completions) == 0
+        with common.ignored(jedi.NotFoundError):  # TODO shouldn't throw that.
+            defs = self.goto_definitions("assert")
+            assert len(defs) == 1
 
     def test_goto_following_on_imports(self):
         s = "import multiprocessing.dummy; multiprocessing.dummy"