src/transformers/models/xmod/modeling_xmod.py/XmodEncoder/__init__
class XmodEncoder:    def __init__(self, config):
        super().__init__()
        self.config = config
        self.layer = nn.ModuleList([XmodLayer(config) for _ in range(config.num_hidden_layers)])
        self.is_pre_norm = config.pre_norm
        if self.is_pre_norm:
            self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
        self.gradient_checkpointing = False