Adding the test "expect_true(inherits()" when using add flat template addins

[ronysym]

During a ThinkR N2 training, in the Bakacode.io environment; When using the Fusen addin: add_flat_template "additonnial", the chunck "test" does not integrate by the test: expect_true(inherits(function_name, "function"))

While when using addins add_chunk this test is included automatically