src/transformers/models/realm/modeling_realm.py/RealmBertModel/__init__
class RealmBertModel:    def __init__(self, config, add_pooling_layer=True):
        super().__init__(config)
        self.config = config

        self.embeddings = RealmEmbeddings(config)
        self.encoder = RealmEncoder(config)

        self.pooler = RealmPooler(config) if add_pooling_layer else None

        # Weights initialization is mostly managed by other Realm models,
        # but we also have them initialized here to keep a consistency.
        self.post_init()