src/transformers/models/bit/modeling_bit.py/BitGroupNormActivation/__init__
class BitGroupNormActivation:    def __init__(self, config, num_channels, eps=1e-5, affine=True, apply_activation=True):
        super(BitGroupNormActivation, self).__init__(config.num_groups, num_channels, eps=eps, affine=affine)
        if apply_activation:
            self.activation = ACT2FN[config.hidden_act]
        else:
            self.activation = nn.Identity()