We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Support AutoScalingCreationPolicy
From the docs, this is a top-level property of a [CreationPolicy](http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-creationpolicy.html#cfn-attributes-creationpolicy-properties). It is used for the [AutoScalingReplacingPolicy](http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-updatepolicy.html#cfn-attributes-updatepolicy-replacingupdate) to specify the MinSuccessfulInstancesPercent property.

The docs have a good example of this:

``` json
"UpdatePolicy" : {
  "AutoScalingReplacingUpdate" : {
    "WillReplace" : "true"
  },
"CreationPolicy" : {
  "ResourceSignal" : {
    "Count" : { "Ref" : "ResourceSignalsOnCreate"},
    "Timeout" : "PT10M"
  },
  "AutoScalingCreationPolicy" : {
    "MinSuccessfulInstancesPercent" : { "Ref" : "MinSuccessfulPercentParameter" }
  }
}
```

I might take a crack at this but I figured I'd file an issue first if only so that I can reference it.


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `troposphere/policies.py`
Content:
```
1 from . import AWSProperty, AWSAttribute, validate_pausetime
2 from .validators import positive_integer, integer, boolean
3 
4 
5 class AutoScalingRollingUpdate(AWSProperty):
6     props = {
7         'MaxBatchSize': (positive_integer, False),
8         'MinInstancesInService': (integer, False),
9         'MinSuccessfulInstancesPercent': (integer, False),
10         'PauseTime': (validate_pausetime, False),
11         'SuspendProcesses': ([basestring], False),
12         'WaitOnResourceSignals': (boolean, False),
13     }
14 
15 
16 class AutoScalingScheduledAction(AWSProperty):
17     props = {
18         'IgnoreUnmodifiedGroupSizeProperties': (boolean, False),
19     }
20 
21 
22 class AutoScalingReplacingUpdate(AWSProperty):
23     props = {
24         'WillReplace': (boolean, False),
25     }
26 
27 
28 class UpdatePolicy(AWSAttribute):
29     props = {
30         'AutoScalingRollingUpdate': (AutoScalingRollingUpdate, False),
31         'AutoScalingScheduledAction': (AutoScalingScheduledAction, False),
32         'AutoScalingReplacingUpdate': (AutoScalingReplacingUpdate, False),
33     }
34 
35 
36 class ResourceSignal(AWSProperty):
37     props = {
38         'Count': (positive_integer, False),
39         'Timeout': (validate_pausetime, False),
40     }
41 
42 
43 class CreationPolicy(AWSAttribute):
44     props = {
45         'ResourceSignal': (ResourceSignal, True),
46     }
47
```
--- 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/troposphere/policies.py b/troposphere/policies.py
--- a/troposphere/policies.py
+++ b/troposphere/policies.py
@@ -40,7 +40,14 @@
     }
 
 
+class AutoScalingCreationPolicy(AWSProperty):
+    props = {
+        'MinSuccessfulInstancesPercent': (integer, False),
+    }
+
+
 class CreationPolicy(AWSAttribute):
     props = {
+        'AutoScalingCreationPolicy': (AutoScalingCreationPolicy, False),
         'ResourceSignal': (ResourceSignal, True),
     }

{"golden_diff": "diff --git a/troposphere/policies.py b/troposphere/policies.py\n--- a/troposphere/policies.py\n+++ b/troposphere/policies.py\n@@ -40,7 +40,14 @@\n     }\n \n \n+class AutoScalingCreationPolicy(AWSProperty):\n+    props = {\n+        'MinSuccessfulInstancesPercent': (integer, False),\n+    }\n+\n+\n class CreationPolicy(AWSAttribute):\n     props = {\n+        'AutoScalingCreationPolicy': (AutoScalingCreationPolicy, False),\n         'ResourceSignal': (ResourceSignal, True),\n     }\n", "issue": "Support AutoScalingCreationPolicy\nFrom the docs, this is a top-level property of a [CreationPolicy](http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-creationpolicy.html#cfn-attributes-creationpolicy-properties). It is used for the [AutoScalingReplacingPolicy](http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-updatepolicy.html#cfn-attributes-updatepolicy-replacingupdate) to specify the MinSuccessfulInstancesPercent property.\n\nThe docs have a good example of this:\n\n``` json\n\"UpdatePolicy\" : {\n  \"AutoScalingReplacingUpdate\" : {\n    \"WillReplace\" : \"true\"\n  },\n\"CreationPolicy\" : {\n  \"ResourceSignal\" : {\n    \"Count\" : { \"Ref\" : \"ResourceSignalsOnCreate\"},\n    \"Timeout\" : \"PT10M\"\n  },\n  \"AutoScalingCreationPolicy\" : {\n    \"MinSuccessfulInstancesPercent\" : { \"Ref\" : \"MinSuccessfulPercentParameter\" }\n  }\n}\n```\n\nI might take a crack at this but I figured I'd file an issue first if only so that I can reference it.\n\n", "before_files": [{"content": "from . import AWSProperty, AWSAttribute, validate_pausetime\nfrom .validators import positive_integer, integer, boolean\n\n\nclass AutoScalingRollingUpdate(AWSProperty):\n    props = {\n        'MaxBatchSize': (positive_integer, False),\n        'MinInstancesInService': (integer, False),\n        'MinSuccessfulInstancesPercent': (integer, False),\n        'PauseTime': (validate_pausetime, False),\n        'SuspendProcesses': ([basestring], False),\n        'WaitOnResourceSignals': (boolean, False),\n    }\n\n\nclass AutoScalingScheduledAction(AWSProperty):\n    props = {\n        'IgnoreUnmodifiedGroupSizeProperties': (boolean, False),\n    }\n\n\nclass AutoScalingReplacingUpdate(AWSProperty):\n    props = {\n        'WillReplace': (boolean, False),\n    }\n\n\nclass UpdatePolicy(AWSAttribute):\n    props = {\n        'AutoScalingRollingUpdate': (AutoScalingRollingUpdate, False),\n        'AutoScalingScheduledAction': (AutoScalingScheduledAction, False),\n        'AutoScalingReplacingUpdate': (AutoScalingReplacingUpdate, False),\n    }\n\n\nclass ResourceSignal(AWSProperty):\n    props = {\n        'Count': (positive_integer, False),\n        'Timeout': (validate_pausetime, False),\n    }\n\n\nclass CreationPolicy(AWSAttribute):\n    props = {\n        'ResourceSignal': (ResourceSignal, True),\n    }\n", "path": "troposphere/policies.py"}], "after_files": [{"content": "from . import AWSProperty, AWSAttribute, validate_pausetime\nfrom .validators import positive_integer, integer, boolean\n\n\nclass AutoScalingRollingUpdate(AWSProperty):\n    props = {\n        'MaxBatchSize': (positive_integer, False),\n        'MinInstancesInService': (integer, False),\n        'MinSuccessfulInstancesPercent': (integer, False),\n        'PauseTime': (validate_pausetime, False),\n        'SuspendProcesses': ([basestring], False),\n        'WaitOnResourceSignals': (boolean, False),\n    }\n\n\nclass AutoScalingScheduledAction(AWSProperty):\n    props = {\n        'IgnoreUnmodifiedGroupSizeProperties': (boolean, False),\n    }\n\n\nclass AutoScalingReplacingUpdate(AWSProperty):\n    props = {\n        'WillReplace': (boolean, False),\n    }\n\n\nclass UpdatePolicy(AWSAttribute):\n    props = {\n        'AutoScalingRollingUpdate': (AutoScalingRollingUpdate, False),\n        'AutoScalingScheduledAction': (AutoScalingScheduledAction, False),\n        'AutoScalingReplacingUpdate': (AutoScalingReplacingUpdate, False),\n    }\n\n\nclass ResourceSignal(AWSProperty):\n    props = {\n        'Count': (positive_integer, False),\n        'Timeout': (validate_pausetime, False),\n    }\n\n\nclass AutoScalingCreationPolicy(AWSProperty):\n    props = {\n        'MinSuccessfulInstancesPercent': (integer, False),\n    }\n\n\nclass CreationPolicy(AWSAttribute):\n    props = {\n        'AutoScalingCreationPolicy': (AutoScalingCreationPolicy, False),\n        'ResourceSignal': (ResourceSignal, True),\n    }\n", "path": "troposphere/policies.py"}]}