We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Unable to launch the debugger
Getting the following error in master when debugging in VSC:
```
Could not connect to None: 60857
Traceback (most recent call last):
  File "/Users/donjayamanne/Desktop/Development/vscode/ptvsd/ptvsd/pydevd/pydevd.py", line 1620, in main
    debugger.connect(host, port)
  File "/Users/donjayamanne/Desktop/Development/vscode/ptvsd/ptvsd/pydevd/pydevd.py", line 326, in connect
    s = start_server(port)
  File "/Users/donjayamanne/Desktop/Development/vscode/ptvsd/ptvsd/wrapper.py", line 1766, in start_server
    server = _create_server(port)
  File "/Users/donjayamanne/Desktop/Development/vscode/ptvsd/ptvsd/wrapper.py", line 1701, in _create_server
    server.bind(('127.0.0.1', port))
OSError: [Errno 48] Address already in u
```

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `ptvsd/debugger.py`
Content:
```
1 # Copyright (c) Microsoft Corporation. All rights reserved.
2 # Licensed under the MIT License. See LICENSE in the project root
3 # for license information.
4 
5 from ptvsd.__main__ import run_module, run_file
6 
7 
8 __author__ = "Microsoft Corporation <ptvshelp@microsoft.com>"
9 __version__ = "4.0.0a5"
10 
11 # TODO: not needed?
12 DONT_DEBUG = []
13 
14 
15 def debug(filename, port_num, debug_id, debug_options, run_as, **kwargs):
16     # TODO: docstring
17     address = (None, port_num)
18     if run_as == 'module':
19         run_module(address, filename, **kwargs)
20     else:
21         run_file(address, filename, **kwargs)
22
```
--- 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()

```

diff --git a/ptvsd/debugger.py b/ptvsd/debugger.py
--- a/ptvsd/debugger.py
+++ b/ptvsd/debugger.py
@@ -14,7 +14,7 @@
 
 def debug(filename, port_num, debug_id, debug_options, run_as, **kwargs):
     # TODO: docstring
-    address = (None, port_num)
+    address = ('localhost', port_num)
     if run_as == 'module':
         run_module(address, filename, **kwargs)
     else:

{"golden_diff": "diff --git a/ptvsd/debugger.py b/ptvsd/debugger.py\n--- a/ptvsd/debugger.py\n+++ b/ptvsd/debugger.py\n@@ -14,7 +14,7 @@\n \n def debug(filename, port_num, debug_id, debug_options, run_as, **kwargs):\n     # TODO: docstring\n-    address = (None, port_num)\n+    address = ('localhost', port_num)\n     if run_as == 'module':\n         run_module(address, filename, **kwargs)\n     else:\n", "issue": "Unable to launch the debugger\nGetting the following error in master when debugging in VSC:\r\n```\r\nCould not connect to None: 60857\r\nTraceback (most recent call last):\r\n  File \"/Users/donjayamanne/Desktop/Development/vscode/ptvsd/ptvsd/pydevd/pydevd.py\", line 1620, in main\r\n    debugger.connect(host, port)\r\n  File \"/Users/donjayamanne/Desktop/Development/vscode/ptvsd/ptvsd/pydevd/pydevd.py\", line 326, in connect\r\n    s = start_server(port)\r\n  File \"/Users/donjayamanne/Desktop/Development/vscode/ptvsd/ptvsd/wrapper.py\", line 1766, in start_server\r\n    server = _create_server(port)\r\n  File \"/Users/donjayamanne/Desktop/Development/vscode/ptvsd/ptvsd/wrapper.py\", line 1701, in _create_server\r\n    server.bind(('127.0.0.1', port))\r\nOSError: [Errno 48] Address already in u\r\n```\n", "before_files": [{"content": "# Copyright (c) Microsoft Corporation. All rights reserved.\n# Licensed under the MIT License. See LICENSE in the project root\n# for license information.\n\nfrom ptvsd.__main__ import run_module, run_file\n\n\n__author__ = \"Microsoft Corporation <ptvshelp@microsoft.com>\"\n__version__ = \"4.0.0a5\"\n\n# TODO: not needed?\nDONT_DEBUG = []\n\n\ndef debug(filename, port_num, debug_id, debug_options, run_as, **kwargs):\n    # TODO: docstring\n    address = (None, port_num)\n    if run_as == 'module':\n        run_module(address, filename, **kwargs)\n    else:\n        run_file(address, filename, **kwargs)\n", "path": "ptvsd/debugger.py"}], "after_files": [{"content": "# Copyright (c) Microsoft Corporation. All rights reserved.\n# Licensed under the MIT License. See LICENSE in the project root\n# for license information.\n\nfrom ptvsd.__main__ import run_module, run_file\n\n\n__author__ = \"Microsoft Corporation <ptvshelp@microsoft.com>\"\n__version__ = \"4.0.0a5\"\n\n# TODO: not needed?\nDONT_DEBUG = []\n\n\ndef debug(filename, port_num, debug_id, debug_options, run_as, **kwargs):\n    # TODO: docstring\n    address = ('localhost', port_num)\n    if run_as == 'module':\n        run_module(address, filename, **kwargs)\n    else:\n        run_file(address, filename, **kwargs)\n", "path": "ptvsd/debugger.py"}]}