code: def mask_to_weights(mask):
      return mask.astype(np.float32) / np.count_nonzero(mask)
  
file_path: spektral/examples/node_prediction/citation_gcn.py
imports: import numpy
  import tensorflow
  from tensorflow.keras.callbacks import EarlyStopping
  from tensorflow.keras.losses import CategoricalCrossentropy
  from tensorflow.keras.optimizers import Adam
  from spektral.data.loaders import SingleLoader
  from spektral.datasets.citation import Citation
  from spektral.layers import GCNConv
  from spektral.models.gcn import GCN
  from spektral.transforms import LayerPreprocess
label_desc: Use image node_id 1 for calling a global function with example usage: mask_to_weights(mask) and returns: unknown