# Configuration The base class [`PreTrainedConfig`] implements the common methods for loading/saving a configuration either from a local file or directory, or from a pretrained model configuration provided by the library (downloaded from HuggingFace's AWS S3 repository). Each derived config class implements model specific attributes. Common attributes present in all config classes are: `hidden_size`, `num_attention_heads`, and `num_hidden_layers`. Text models further implement: `vocab_size`. ## PreTrainedConfig [[autodoc]] PreTrainedConfig - push_to_hub - all