title: Tensorflow fails with the error: InvalidArgumentError: Node 'initial_state': Unknown input node 'initial_state/input'
body: <p>The source-code with the entire exception trace can be found <a href="https://github.com/apiltamang/deep-learning/blob/master/tv-script-generation/dlnd_tv_script_generation.ipynb" rel="nofollow noreferrer">here</a>. This is very weird because it occurs in the tf.global_variables_initializer() method in the "Train" section of the code. Why would this method fail trying to get the "initial_state" variable? The line right above it shows that this variable is clearly present in global scope.</p>
  
  <p>The code is part of a MOOC, and strangely enough nobody else in the class (>5000) seems to have experienced that problem...</p>
  
  <p>Hmmm..What could I be missing..</p>