lfads: Where is train_modelvals defined?

[cclauss]

@jazcollins Do you know where is train_modelvals defined?

flake8 testing of https://github.com/tensorflow/models on Python 2.7.13

$ flake8 --count --select=E901,E999,F821,F822,F823 --show-source --statistics lfads

./lfads/plot_lfads.py:55:24: F821 undefined name 'train_modelvals'
  g0s_prior_mean_bxn = train_modelvals['prior_g0_mean']
                       ^

./lfads/plot_lfads.py:56:23: F821 undefined name 'train_modelvals'
  g0s_prior_var_bxn = train_modelvals['prior_g0_var']
                      ^

./lfads/plot_lfads.py:57:23: F821 undefined name 'train_modelvals'
  g0s_post_mean_bxn = train_modelvals['posterior_g0_mean']
                      ^

./lfads/plot_lfads.py:58:22: F821 undefined name 'train_modelvals'
  g0s_post_var_bxn = train_modelvals['posterior_g0_var']
                     ^