def build_dla_backbone(cfg, input_shape):
    """
    Parameters
    ----------
    cfg: CfgNode
        [description]

    input_shape: ShapeSpec
        [description]
    """
    assert input_shape.channels == 3, "Only supports 3-channel input for now."

    builder = DLA_NAME_TO_BUILDER[cfg.NAME]
    return builder(cfg)

    Parameters
    ----------
    cfg: CfgNode
        [description]

    input_shape: ShapeSpec
        [description]
    
tridet/modeling/feature_extractor/dla.py