Performs a forward pass through the DkNN on a TF tensor by wrapping
    the fprop_np method.

def fprop(self, x):
    """
    Performs a forward pass through the DkNN on a TF tensor by wrapping
    the fprop_np method.
    """
    logits = tf.py_func(self.fprop_np, [x], tf.float32)
    return {self.O_LOGITS: logits}