prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  Add an environment variable to skip nltk.download()
  
  Add an environment variable to skip nltk.download()
  
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `deeppavlov/models/__init__.py`
  Content:
  ```
  1 # Copyright 2017 Neural Networks and Deep Learning lab, MIPT
  2 #
  3 # Licensed under the Apache License, Version 2.0 (the "License");
  4 # you may not use this file except in compliance with the License.
  5 # You may obtain a copy of the License at
  6 #
  7 #     http://www.apache.org/licenses/LICENSE-2.0
  8 #
  9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14 
  15 import nltk
  16 
  17 from deeppavlov.core.common.prints import RedirectedPrints
  18 
  19 
  20 with RedirectedPrints():
  21     nltk.download('punkt')
  22     nltk.download('stopwords')
  23     nltk.download('perluniprops')
  24     nltk.download('nonbreaking_prefixes')
  25
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/deeppavlov/models/__init__.py b/deeppavlov/models/__init__.py
  --- a/deeppavlov/models/__init__.py
  +++ b/deeppavlov/models/__init__.py
  @@ -12,13 +12,14 @@
   # See the License for the specific language governing permissions and
   # limitations under the License.
   
  +import os
   import nltk
   
   from deeppavlov.core.common.prints import RedirectedPrints
   
  -
  -with RedirectedPrints():
  -    nltk.download('punkt')
  -    nltk.download('stopwords')
  -    nltk.download('perluniprops')
  -    nltk.download('nonbreaking_prefixes')
  +if not os.environ.get('DP_SKIP_NLTK_DOWNLOAD'):
  +    with RedirectedPrints():
  +        nltk.download('punkt')
  +        nltk.download('stopwords')
  +        nltk.download('perluniprops')
  +        nltk.download('nonbreaking_prefixes')
  
verification_info: {"golden_diff": "diff --git a/deeppavlov/models/__init__.py b/deeppavlov/models/__init__.py\n--- a/deeppavlov/models/__init__.py\n+++ b/deeppavlov/models/__init__.py\n@@ -12,13 +12,14 @@\n # See the License for the specific language governing permissions and\n # limitations under the License.\n \n+import os\n import nltk\n \n from deeppavlov.core.common.prints import RedirectedPrints\n \n-\n-with RedirectedPrints():\n-    nltk.download('punkt')\n-    nltk.download('stopwords')\n-    nltk.download('perluniprops')\n-    nltk.download('nonbreaking_prefixes')\n+if not os.environ.get('DP_SKIP_NLTK_DOWNLOAD'):\n+    with RedirectedPrints():\n+        nltk.download('punkt')\n+        nltk.download('stopwords')\n+        nltk.download('perluniprops')\n+        nltk.download('nonbreaking_prefixes')\n", "issue": "Add an environment variable to skip nltk.download()\n\nAdd an environment variable to skip nltk.download()\n\n", "before_files": [{"content": "# Copyright 2017 Neural Networks and Deep Learning lab, MIPT\n#\n# Licensed under the Apache License, Version 2.0 (the \"License\");\n# you may not use this file except in compliance with the License.\n# You may obtain a copy of the License at\n#\n#     http://www.apache.org/licenses/LICENSE-2.0\n#\n# Unless required by applicable law or agreed to in writing, software\n# distributed under the License is distributed on an \"AS IS\" BASIS,\n# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n# See the License for the specific language governing permissions and\n# limitations under the License.\n\nimport nltk\n\nfrom deeppavlov.core.common.prints import RedirectedPrints\n\n\nwith RedirectedPrints():\n    nltk.download('punkt')\n    nltk.download('stopwords')\n    nltk.download('perluniprops')\n    nltk.download('nonbreaking_prefixes')\n", "path": "deeppavlov/models/__init__.py"}], "after_files": [{"content": "# Copyright 2017 Neural Networks and Deep Learning lab, MIPT\n#\n# Licensed under the Apache License, Version 2.0 (the \"License\");\n# you may not use this file except in compliance with the License.\n# You may obtain a copy of the License at\n#\n#     http://www.apache.org/licenses/LICENSE-2.0\n#\n# Unless required by applicable law or agreed to in writing, software\n# distributed under the License is distributed on an \"AS IS\" BASIS,\n# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n# See the License for the specific language governing permissions and\n# limitations under the License.\n\nimport os\nimport nltk\n\nfrom deeppavlov.core.common.prints import RedirectedPrints\n\nif not os.environ.get('DP_SKIP_NLTK_DOWNLOAD'):\n    with RedirectedPrints():\n        nltk.download('punkt')\n        nltk.download('stopwords')\n        nltk.download('perluniprops')\n        nltk.download('nonbreaking_prefixes')\n", "path": "deeppavlov/models/__init__.py"}]}