code: def collate(self) -> Callable:
      return fastface_collate_fn
  
file_path: lightning-flash/src/flash/image/face_detection/input_transform.py
imports: from dataclasses import dataclass
  from typing import Any, Callable, Dict, Sequence
  import torch
  from flash.core.data.io.input import DataKeys
  from flash.core.data.io.input_transform import InputTransform
  from flash.core.data.transforms import ApplyToKeys
  from flash.core.utilities.imports import _FASTFACE_AVAILABLE, _TORCHVISION_AVAILABLE
label_desc: Use image node_id 2 for calling the FaceDetectionInputTransform obj's underlying member method code with example usage: obj.collate() and returns: fastface_collate_fn