title: Shapes (1,) and () are not compatible on cond operator
body: <p>I want to skip some data that have specific labels (like if <code>label</code> >= 7 or other). My code is here:</p>
  
  <pre><code>true = tf.constant(True)
  less_op = tf.less(label, tf.constant(delimiter))
  label = tf.cast(
      tf.slice(record_bytes, [0], [label_bytes]), tf.int32)
  tf.cond(less_op, lambda: true, lambda: true)
  </code></pre>
  
  <p>and on the 4th line I have error: <code>ValueError: Shapes (1,) and () are not compatible</code>. My assumption that it's caused by less_op (if I substitute it with <code>true</code> code works). Also I investigated that there is some problem with <code>label</code>: code <code>less_op = tf.less(tf.constant(1), tf.constant(delimiter))</code> works perfectly.</p>