src/transformers/models/albert/modeling_albert.py/AlbertTransformer/__init__
class AlbertTransformer:    def __init__(self, config):
        super().__init__()

        self.config = config
        self.embedding_hidden_mapping_in = nn.Linear(config.embedding_size, config.hidden_size)
        self.albert_layer_groups = nn.ModuleList([AlbertLayerGroup(config) for _ in range(config.num_hidden_groups)])