title: How to input a list of lists with different sizes in tf.data.Dataset
body: <p>I have a long list of lists of integers (representing sentences, each one of different sizes) that I want to feed using the tf.data library. Each list (of the lists of list) has different length, and I get an error, which I can reproduce here:</p>
  
  <pre><code>t = [[4,2], [3,4,5]]
  dataset = tf.data.Dataset.from_tensor_slices(t)
  </code></pre>
  
  <p>The error I get is:</p>
  
  <pre><code>ValueError: Argument must be a dense tensor: [[4, 2], [3, 4, 5]] - got shape [2], but wanted [2, 2].
  </code></pre>
  
  <p>Is there a way to do this?</p>
  
  <p>EDIT 1: Just to be clear, I don't want to pad the input list of lists (it's a list of sentences containing over a million elements, with varying lengths) I want to use the tf.data library to feed, in a proper way, a list of lists with varying length.</p>