class_docstr: Abstract generator class.
      
docstr: Preprocess image and its annotations.
          
code: def preprocess_group_entry(self, image, annotations):
      """Preprocess image and its annotations."""
      # resize image
      image, image_scale = self.resize_image(image)
  
      # preprocess the image
      image = self.preprocess_image(image)
  
      # apply resizing to annotations too
      annotations["bboxes"] *= image_scale
  
      # convert to the wanted keras floatx
      image = keras.backend.cast_to_floatx(image)
  
      return image, annotations
  
imports: import numpy
  import random
  import warnings
  from tensorflow import keras
  from ..utils.anchors import anchor_targets_bbox, anchors_for_shape, guess_shapes
  from ..utils.config import parse_anchor_parameters, parse_pyramid_levels
  from ..utils.image import TransformParameters, adjust_transform_for_image, apply_transform, preprocess_image, resize_image
  from ..utils.transform import transform_aabb
label_desc: Use image node_id 21 for calling the Generator obj's underlying member method code with example usage: obj.preprocess_group_entry(image, annotations) and returns: image,  annotations