Not able to specify string input in radish steps

I'm trying to check for a string in the feature file and am trying to get that string using {variable:w} . But this just raises an unimplemented error.

I've tried all the data types listed in the documentation , only a few of them seem to work. I also tried {} but it returns the whole sentence.

Feature: New Feature
    Scenario:Test
        Given I make a call
        Then I expect "Hello"

@given("I make a call")
def make_call(step):
    step.context.actual_result = "Hello"

@then("I expect {result:w}")
def expect_result(step,result):
    print(type(result))
    assert step.context.actual_result == result

I get this error

@step(r"Then I expect "Hello"")
def my_step(step):
    raise NotImplementedError("This step is not implemented yet")

But it should assert the two strings and pass the test