n_layers: 2                     # (int) The number of transformer layers in transformer encoder.
n_heads: 2                      # (int) The number of attention heads for multi-head attention layer.
hidden_size: 64                 # (int) The number of features in the hidden state.
inner_size: 256                 # (int) The inner hidden size in feed-forward layer.
hidden_dropout_prob: 0.5        # (float) The probability of an element to be zeroed.
attn_dropout_prob: 0.5          # (float) The probability of an attention score to be zeroed.
hidden_act: 'gelu'              # (str) The activation function in feed-forward layer.
layer_norm_eps: 1e-12           # (float) A value added to the denominator for numerical stability. 
initializer_range: 0.02         # (float) The standard deviation for normal initialization.
selected_features: ['class']    # (list of str) The list of selected item features. 
pooling_mode: 'sum'             # (str) Intra-feature pooling mode. Range in ['max', 'mean', 'sum'].
loss_type: 'CE'                 # (str) The type of loss function. Range in ['BPR', 'CE'].