code: def __init__(self, in_channels, num_anchors, num_classes):
      self.classification_head = ClassificationHead(
          in_channels, num_anchors, num_classes
      )
      self.regression_head = RegressionHead(in_channels, num_anchors)
  
imports: import math
  from tinygrad.helpers import flatten, get_child
  import tinygrad.nn
  from extra.models.resnet import ResNet
  import numpy
label_desc: Use image node_id 1 to create a new RetinaHead object  with example: obj = RetinaHead(in_channels, num_anchors, num_classes)