The documentation page API/MODELS/&AMP;NUM;DIFFUSERS.PRIORTRANSFORMER.NUM_ATTENTION_HEADS doesn’t exist in v0.30.1, but exists on the main version. Click <a href="/docs/diffusers/main/en/api/models/&amp;num;diffusers.PriorTransformer.num_attention_heads">here</a> to redirect to the main version of the documentation.