src/transformers/models/bridgetower/modeling_bridgetower.py/BridgeTowerVisionTransformer/__init__
class BridgeTowerVisionTransformer:    def __init__(self, config):
        super().__init__()

        self.embeddings = BridgeTowerVisionEmbeddings(config)
        self.ln_pre = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.transformer = BridgeTowerTransformer(config)
        self.ln_post = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.share_layernorm = config.share_layernorm
        if not config.share_layernorm:
            self.ln_separate = nn.ModuleList(
                [nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps) for _ in range(config.num_hidden_layers)]
            )