code: def backbone(backbone_name):
      """Returns a backbone object for the given backbone."""
      if "densenet" in backbone_name:
          from .densenet import DenseNetBackbone as b
      elif (
          "seresnext" in backbone_name
          or "seresnet" in backbone_name
          or "senet" in backbone_name
      ):
          from .senet import SeBackbone as b
      elif "resnet" in backbone_name:
          from .resnet import ResNetBackbone as b
      elif "mobilenet" in backbone_name:
          from .mobilenet import MobileNetBackbone as b
      elif "vgg" in backbone_name:
          from .vgg import VGGBackbone as b
      elif "EfficientNet" in backbone_name:
          from .effnet import EfficientNetBackbone as b
      else:
          raise NotImplementedError(
              "Backbone class for  '{}' not implemented.".format(
                  backbone
              )
          )
  
      return b(backbone_name)
  
file_path: ImageAI/imageai_tf_deprecated/Detection/keras_retinanet/models/__init__.py
imports: from __future__ import print_function
  import sys
label_desc: Use image node_id 1 for calling a global function with example usage: backbone(backbone_name) and returns: b