[BE] Delete from __future__ import (#2429)

As Python-2.7 is long past EOL, and all tutorials are living in the future :)

Author: malfet

advanced_source/cpp_frontend.rst

@@ -1216,9 +1216,6 @@ tensors and display them with matplotlib:
 
 .. code-block:: python
 
-  from __future__ import print_function
-  from __future__ import unicode_literals
-
   import argparse
 
   import matplotlib.pyplot as plt

advanced_source/neural_style_tutorial.py

@@ -47,8 +47,6 @@
 # -  ``torchvision.models`` (train or load pretrained models)
 # -  ``copy`` (to deep copy the models; system package)
 
-from __future__ import print_function
-
 import torch
 import torch.nn as nn
 import torch.nn.functional as F

beginner_source/chatbot_tutorial.py

@@ -92,11 +92,6 @@
 # After that, let’s import some necessities.
 #
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
-
 import torch
 from torch.jit import script, trace
 import torch.nn as nn

beginner_source/data_loading_tutorial.py

@@ -18,7 +18,6 @@
 
 """
 
-from __future__ import print_function, division
 import os
 import torch
 import pandas as pd

beginner_source/deploy_seq2seq_hybrid_frontend_tutorial.py

@@ -101,11 +101,6 @@
 # maximum length output that the model is capable of producing.
 #
 
-from __future__ import absolute_import
-from __future__ import division
-from __future__ import print_function
-from __future__ import unicode_literals
-
 import torch
 import torch.nn as nn
 import torch.nn.functional as F

beginner_source/fgsm_tutorial.py

@@ -90,7 +90,6 @@
 # into the implementation.
 # 
 
-from __future__ import print_function
 import torch
 import torch.nn as nn
 import torch.nn.functional as F

beginner_source/transfer_learning_tutorial.py

@@ -33,8 +33,6 @@
 # License: BSD
 # Author: Sasank Chilamkurthy
 
-from __future__ import print_function, division
-
 import torch
 import torch.nn as nn
 import torch.optim as optim

intermediate_source/char_rnn_classification_tutorial.py

@@ -74,7 +74,6 @@
 ``{language: [names ...]}``. The generic variables "category" and "line"
 (for language and name in our case) are used for later extensibility.
 """
-from __future__ import unicode_literals, print_function, division
 from io import open
 import glob
 import os

intermediate_source/char_rnn_generation_tutorial.py

@@ -75,7 +75,6 @@
 and end up with a dictionary ``{language: [names ...]}``.
 
 """
-from __future__ import unicode_literals, print_function, division
 from io import open
 import glob
 import os

intermediate_source/dynamic_quantization_bert_tutorial.rst

@@ -92,8 +92,6 @@ In this step we import the necessary Python modules for the tutorial.
 
 .. code:: python
 
-    from __future__ import absolute_import, division, print_function
-
     import logging
     import numpy as np
     import os