code: def preprocess_input(x, dim_ordering="default"):
      if dim_ordering == "default":
          dim_ordering = K.image_dim_ordering()
      assert dim_ordering in {"tf", "th"}
  
      if dim_ordering == "th":
          x[:, 0, :, :] -= 103.939
          x[:, 1, :, :] -= 116.779
          x[:, 2, :, :] -= 123.68
          # 'RGB'->'BGR'
          x = x[:, ::-1, :, :]
      else:
          x[:, :, :, 0] -= 103.939
          x[:, :, :, 1] -= 116.779
          x[:, :, :, 2] -= 123.68
          # 'RGB'->'BGR'
          x = x[:, :, :, ::-1]
      return x
  
imports: import numpy
  import json
  from keras.utils.data_utils import get_file
  from keras import backend
label_desc: Use image node_id 1 for calling a global function with example usage: preprocess_input(x, dim_ordering) and returns: x