IPNDMScheduler  
A fourth-order Improved Pseudo Linear Multistep scheduler.  
This model inherits from [`SchedulerMixin`] and [`ConfigMixin`]. Check the superclass documentation for the generic
methods the library implements for all schedulers such as loading and saving.  
Args:
num_train_timesteps (`int`, defaults to 1000):
The number of diffusion steps to train the model.
trained_betas (`np.ndarray`, *optional*):
Pass an array of betas directly to the constructor to bypass `beta_start` and `beta_end`.