prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  BBAN for en_GB too short
  * Faker version: v2.0.3
  * OS: linux
  
  Numeric part of the en_GB BBAN needs to be 14 digits long, it currently only returns 13, failing further validation.
  
  ### Steps to reproduce
  
  Invoke `fake.iban()` or `fake.bban()` with the en_GB locale, an IBAN or BBAN with 1 digit missing is returned.
  
  ### Expected behavior
  
  GB ibans should be 22 chars long: https://www.xe.com/ibancalculator/sample/?ibancountry=united kingdom
  
  
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `faker/providers/bank/en_GB/__init__.py`
  Content:
  ```
  1 from .. import Provider as BankProvider
  2 
  3 
  4 class Provider(BankProvider):
  5     bban_format = '????#############'
  6     country_code = 'GB'
  7
  ```
  --- 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/faker/providers/bank/en_GB/__init__.py b/faker/providers/bank/en_GB/__init__.py
  --- a/faker/providers/bank/en_GB/__init__.py
  +++ b/faker/providers/bank/en_GB/__init__.py
  @@ -2,5 +2,5 @@
   
   
   class Provider(BankProvider):
  -    bban_format = '????#############'
  +    bban_format = '????##############'
       country_code = 'GB'
  
verification_info: {"golden_diff": "diff --git a/faker/providers/bank/en_GB/__init__.py b/faker/providers/bank/en_GB/__init__.py\n--- a/faker/providers/bank/en_GB/__init__.py\n+++ b/faker/providers/bank/en_GB/__init__.py\n@@ -2,5 +2,5 @@\n \n \n class Provider(BankProvider):\n-    bban_format = '????#############'\n+    bban_format = '????##############'\n     country_code = 'GB'\n", "issue": "BBAN for en_GB too short\n* Faker version: v2.0.3\r\n* OS: linux\r\n\r\nNumeric part of the en_GB BBAN needs to be 14 digits long, it currently only returns 13, failing further validation.\r\n\r\n### Steps to reproduce\r\n\r\nInvoke `fake.iban()` or `fake.bban()` with the en_GB locale, an IBAN or BBAN with 1 digit missing is returned.\r\n\r\n### Expected behavior\r\n\r\nGB ibans should be 22 chars long: https://www.xe.com/ibancalculator/sample/?ibancountry=united kingdom\r\n\r\n\n", "before_files": [{"content": "from .. import Provider as BankProvider\n\n\nclass Provider(BankProvider):\n    bban_format = '????#############'\n    country_code = 'GB'\n", "path": "faker/providers/bank/en_GB/__init__.py"}], "after_files": [{"content": "from .. import Provider as BankProvider\n\n\nclass Provider(BankProvider):\n    bban_format = '????##############'\n    country_code = 'GB'\n", "path": "faker/providers/bank/en_GB/__init__.py"}]}