def _initialise(self, initial_state: str = 'unknown') -> dict:
        """Return a dictionary used to initialise a state object.

        This method is used to obtain a dictionary/hash describing the initial
        state of SDP or a service in SDP.

        Args:
            initial_state (str): Initial state.

        Returns:
            dict, Initial state configuration

        """
        initial_state = initial_state.lower()
        if initial_state != 'unknown' and \
                initial_state not in self._allowed_states:
            raise ValueError('Invalid initial state: {}'.format(initial_state))
        _initial_state = dict(
            current_state=initial_state,
            target_state=initial_state,
            current_timestamp=datetime.utcnow().isoformat(),
            target_timestamp=datetime.utcnow().isoformat())
        return _initial_state
Return a dictionary used to initialise a state object.

        This method is used to obtain a dictionary/hash describing the initial
        state of SDP or a service in SDP.

        Args:
            initial_state (str): Initial state.

        Returns:
            dict, Initial state configuration