code: def l2_norm(params):
      """Computes l2 norm of params by flattening them into a vector."""
      flattened, _ = flatten(params)
      return np.dot(flattened, flattened)
  
file_path: autograd/examples/neural_net.py
imports: from __future__ import absolute_import, division
  from __future__ import print_function
  import autograd.numpy
  import autograd.numpy.random
  from autograd.scipy.special import logsumexp
  from autograd import grad
  from autograd.misc.flatten import flatten
  from autograd.misc.optimizers import adam
  from data import load_mnist
label_desc: Use image node_id 3 for calling a global function with example usage: l2_norm(params) and returns: np