src/transformers/models/megatron_bert/modeling_megatron_bert.py/MegatronBertEncoder/__init__
class MegatronBertEncoder:    def __init__(self, config):
        super().__init__()
        self.config = config
        self.layer = nn.ModuleList([MegatronBertLayer(config) for _ in range(config.num_hidden_layers)])

        # The final layer norm. We removed the 1st LN, moved LN to each hidden layer and this one
        # is simply the final LN (Transformer's BERT has it attached to each hidden layer).
        self.ln = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)