def __init__(
            self,
            *,
            backbone,
            heads,
            pixel_mean,
            pixel_std,
            loss_kwargs=None
    ):
        """
        NOTE: this interface is experimental.

        Args:
            backbone:
            heads:
            pixel_mean:
            pixel_std:
        """
        super().__init__()
        # backbone
        self.backbone = backbone

        # head
        self.heads = heads

        self.loss_kwargs = loss_kwargs

        self.register_buffer('pixel_mean', torch.Tensor(pixel_mean).view(1, -1, 1, 1), False)
        self.register_buffer('pixel_std', torch.Tensor(pixel_std).view(1, -1, 1, 1), False)

        NOTE: this interface is experimental.

        Args:
            backbone:
            heads:
            pixel_mean:
            pixel_std:
        
fastreid/modeling/meta_arch/baseline.py