Rewrite all state declarations that look like this::

      state_id_decl:
        state.func

    into::

      state_id_decl:
        state.func: []

def rewrite_single_shorthand_state_decl(data):  # pylint: disable=C0103
    '''
    Rewrite all state declarations that look like this::

      state_id_decl:
        state.func

    into::

      state_id_decl:
        state.func: []
    '''
    for sid, states in six.iteritems(data):
        if isinstance(states, six.string_types):
            data[sid] = {states: []}