def constant_schedule(init_step_size: float) -> StepSchedule:
    """Create a constant step schedule.

    Parameters
    ----------
    init_step_size: float
        The step size.

    Returns
    -------
    schedule_fn: StepSchedule
    """
    if not init_step_size >= 0:
        raise ValueError("`init_step_size` should be >= 0.")

    def schedule(_step: Array):
        return init_step_size

    return schedule
Create a constant step schedule.

    Parameters
    ----------
    init_step_size: float
        The step size.

    Returns
    -------
    schedule_fn: StepSchedule
    
fortuna/prob_model/posterior/sgmcmc/sgmcmc_step_schedule.py