code: def ValueLoss(values, returns, value_loss_coeff):
      """Definition of the loss of the value function."""
      advantages = returns - values
      l2_value_loss = jnp.mean(advantages**2) * value_loss_coeff
      return l2_value_loss
  
file_path: trax/trax/rl/rl_layers.py
imports: from trax.fastmath import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: ValueLoss(values, returns, value_loss_coeff) and returns: l2_value_loss