code: def train_op():
      g, v = gv(source, target)
      opt(0.01, g)
      return v
  
file_path: objax/examples/maml/maml.py
imports: import jax.numpy
  import matplotlib.pyplot
  import numpy
  from tqdm import trange
  import objax
label_desc: Use image node_id 4 for calling a global function with example usage: train_op() and returns: v