We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
support@gittip.com still linked several places
Should be support@gratipay.com, right? ;-)


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `gratipay/exceptions.py`
Content:
```
1 """
2 This module contains exceptions shared across application code.
3 """
4 
5 from __future__ import print_function, unicode_literals
6 
7 
8 class ProblemChangingUsername(Exception):
9     def __str__(self):
10         return self.msg.format(self.args[0])
11 
12 class UsernameIsEmpty(ProblemChangingUsername):
13     msg = "You need to provide a username!"
14 
15 class UsernameTooLong(ProblemChangingUsername):
16     msg = "The username '{}' is too long."
17 
18 class UsernameContainsInvalidCharacters(ProblemChangingUsername):
19     msg = "The username '{}' contains invalid characters."
20 
21 class UsernameIsRestricted(ProblemChangingUsername):
22     msg = "The username '{}' is restricted."
23 
24 class UsernameAlreadyTaken(ProblemChangingUsername):
25     msg = "The username '{}' is already taken."
26 
27 
28 class ProblemChangingNumber(Exception):
29     def __str__(self):
30         return self.msg
31 
32 class HasBigTips(ProblemChangingNumber):
33     msg = "You receive tips too large for an individual. Please contact support@gittip.com."
34 
35 
36 class TooGreedy(Exception): pass
37 class NoSelfTipping(Exception): pass
38 class NoTippee(Exception): pass
39 class BadAmount(Exception): pass
40 class UserDoesntAcceptTips(Exception): pass
41 
42 class FailedToReserveUsername(Exception): pass
43 
44 class NegativeBalance(Exception):
45     def __str__(self):
46         return "Negative balance not allowed in this context."
47 
48 class NotWhitelisted(Exception): pass
49 class NoBalancedCustomerHref(Exception): pass
50
```
--- 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/gratipay/exceptions.py b/gratipay/exceptions.py
--- a/gratipay/exceptions.py
+++ b/gratipay/exceptions.py
@@ -30,7 +30,7 @@
         return self.msg
 
 class HasBigTips(ProblemChangingNumber):
-    msg = "You receive tips too large for an individual. Please contact support@gittip.com."
+    msg = "You receive tips too large for an individual. Please contact support@gratipay.com."
 
 
 class TooGreedy(Exception): pass

{"golden_diff": "diff --git a/gratipay/exceptions.py b/gratipay/exceptions.py\n--- a/gratipay/exceptions.py\n+++ b/gratipay/exceptions.py\n@@ -30,7 +30,7 @@\n         return self.msg\n \n class HasBigTips(ProblemChangingNumber):\n-    msg = \"You receive tips too large for an individual. Please contact support@gittip.com.\"\n+    msg = \"You receive tips too large for an individual. Please contact support@gratipay.com.\"\n \n \n class TooGreedy(Exception): pass\n", "issue": "support@gittip.com still linked several places\nShould be support@gratipay.com, right? ;-)\n\n", "before_files": [{"content": "\"\"\"\nThis module contains exceptions shared across application code.\n\"\"\"\n\nfrom __future__ import print_function, unicode_literals\n\n\nclass ProblemChangingUsername(Exception):\n    def __str__(self):\n        return self.msg.format(self.args[0])\n\nclass UsernameIsEmpty(ProblemChangingUsername):\n    msg = \"You need to provide a username!\"\n\nclass UsernameTooLong(ProblemChangingUsername):\n    msg = \"The username '{}' is too long.\"\n\nclass UsernameContainsInvalidCharacters(ProblemChangingUsername):\n    msg = \"The username '{}' contains invalid characters.\"\n\nclass UsernameIsRestricted(ProblemChangingUsername):\n    msg = \"The username '{}' is restricted.\"\n\nclass UsernameAlreadyTaken(ProblemChangingUsername):\n    msg = \"The username '{}' is already taken.\"\n\n\nclass ProblemChangingNumber(Exception):\n    def __str__(self):\n        return self.msg\n\nclass HasBigTips(ProblemChangingNumber):\n    msg = \"You receive tips too large for an individual. Please contact support@gittip.com.\"\n\n\nclass TooGreedy(Exception): pass\nclass NoSelfTipping(Exception): pass\nclass NoTippee(Exception): pass\nclass BadAmount(Exception): pass\nclass UserDoesntAcceptTips(Exception): pass\n\nclass FailedToReserveUsername(Exception): pass\n\nclass NegativeBalance(Exception):\n    def __str__(self):\n        return \"Negative balance not allowed in this context.\"\n\nclass NotWhitelisted(Exception): pass\nclass NoBalancedCustomerHref(Exception): pass\n", "path": "gratipay/exceptions.py"}], "after_files": [{"content": "\"\"\"\nThis module contains exceptions shared across application code.\n\"\"\"\n\nfrom __future__ import print_function, unicode_literals\n\n\nclass ProblemChangingUsername(Exception):\n    def __str__(self):\n        return self.msg.format(self.args[0])\n\nclass UsernameIsEmpty(ProblemChangingUsername):\n    msg = \"You need to provide a username!\"\n\nclass UsernameTooLong(ProblemChangingUsername):\n    msg = \"The username '{}' is too long.\"\n\nclass UsernameContainsInvalidCharacters(ProblemChangingUsername):\n    msg = \"The username '{}' contains invalid characters.\"\n\nclass UsernameIsRestricted(ProblemChangingUsername):\n    msg = \"The username '{}' is restricted.\"\n\nclass UsernameAlreadyTaken(ProblemChangingUsername):\n    msg = \"The username '{}' is already taken.\"\n\n\nclass ProblemChangingNumber(Exception):\n    def __str__(self):\n        return self.msg\n\nclass HasBigTips(ProblemChangingNumber):\n    msg = \"You receive tips too large for an individual. Please contact support@gratipay.com.\"\n\n\nclass TooGreedy(Exception): pass\nclass NoSelfTipping(Exception): pass\nclass NoTippee(Exception): pass\nclass BadAmount(Exception): pass\nclass UserDoesntAcceptTips(Exception): pass\n\nclass FailedToReserveUsername(Exception): pass\n\nclass NegativeBalance(Exception):\n    def __str__(self):\n        return \"Negative balance not allowed in this context.\"\n\nclass NotWhitelisted(Exception): pass\nclass NoBalancedCustomerHref(Exception): pass\n", "path": "gratipay/exceptions.py"}]}