model/configuration_maskrcnn.py

from transformers import PretrainedConfig

class MaskRCNNConfig(PretrainedConfig):
    model_type = "maskrcnn"

    def __init__(
        self,
        num_classes=91,
        hidden_layer=256,
        **kwargs
    ):
        super().__init__(**kwargs)
        self.num_classes = num_classes
        self.hidden_layer = hidden_layer