code: def plot_lc(d):
      
      costs = np.squeeze(d['costs'])
      plt.plot(costs)
      plt.ylabel('cost')
      plt.xlabel('iterations (per hundreds)')
      plt.title("Learning rate =" + str(d["learning_rate"]))
      plt.show()
docs: plot learning curve
  
      Arguments:
      d       Returned by model function. Dictionary containing information about the model.