def _verify_wave_tokens(wave_lane):
    """Validate tokens in a WaveLane string.

    Parameters
    ----------
    wave_lane : str
        A string consisting of the WaveLane tokens.

    Returns
    -------
    Boolean
        True if all the tokens in the WaveLane are valid.

    """
    valid_tokens = {'l', 'h', '.'}
    wave_lane_tokens = list(wave_lane)
    for token in wave_lane_tokens:
        if token not in valid_tokens:
            raise ValueError('Valid tokens are: {}'.format(valid_tokens))
