code: def mean_absolute_error(y_true, y_pred):
      return model_ops.mean(tf.abs(y_pred - y_true), axis=-1)
  
file_path: deepchem/contrib/nn/objectives.py
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import unicode_literals
  from __future__ import absolute_import
  import warnings
  import tensorflow
  from deepchem.nn import model_ops
label_desc: Use image node_id 2 for calling a global function with example usage: mean_absolute_error(y_true, y_pred) and returns: model_ops