betas for stepping the model. Choose from
linear, scaled_linear, squaredcos_cap_v2, or sigmoid.   eta (float) —
The weight of noise for added noise in diffusion step. If its value is between 0.0 and 1.0 it corresponds
to the DDIM scheduler, and if its value is between -0.0 and 1.0 it corresponds to the DDPM scheduler.   trained_betas (np.ndarray, optional) —
Pass an array of betas directly to the constructor to bypass beta_start and beta_end.  