We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
RDS VPC example instance classes are out of date
https://github.com/cloudtools/troposphere/blob/565247a50bd27a8f45c3e408b466b193473cb9a6/examples/RDS_VPC.py#L67-L76

The current list of instance classes is documented here: https://aws.amazon.com/rds/instance-types/

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `examples/RDS_VPC.py`
Content:
```
1 # Converted from RDS_VPC.template located at:
2 # http://aws.amazon.com/cloudformation/aws-cloudformation-templates/
3 
4 from troposphere import GetAtt, Join, Output, Parameter, Ref, Template
5 from troposphere.ec2 import SecurityGroup
6 from troposphere.rds import DBInstance, DBSubnetGroup
7 
8 
9 t = Template()
10 
11 t.add_description(
12     "AWS CloudFormation Sample Template VPC_RDS_DB_Instance: Sample template "
13     "showing how to create an RDS DBInstance in an existing Virtual Private "
14     "Cloud (VPC). **WARNING** This template creates an Amazon Relational "
15     "Database Service database instance. You will be billed for the AWS "
16     "resources used if you create a stack from this template.")
17 
18 vpcid = t.add_parameter(Parameter(
19     "VpcId",
20     Type="String",
21     Description="VpcId of your existing Virtual Private Cloud (VPC)"
22 ))
23 
24 subnet = t.add_parameter(Parameter(
25     "Subnets",
26     Type="CommaDelimitedList",
27     Description=(
28         "The list of SubnetIds, for at least two Availability Zones in the "
29         "region in your Virtual Private Cloud (VPC)")
30 ))
31 
32 dbname = t.add_parameter(Parameter(
33     "DBName",
34     Default="MyDatabase",
35     Description="The database name",
36     Type="String",
37     MinLength="1",
38     MaxLength="64",
39     AllowedPattern="[a-zA-Z][a-zA-Z0-9]*",
40     ConstraintDescription=("must begin with a letter and contain only"
41                            " alphanumeric characters.")
42 ))
43 
44 dbuser = t.add_parameter(Parameter(
45     "DBUser",
46     NoEcho=True,
47     Description="The database admin account username",
48     Type="String",
49     MinLength="1",
50     MaxLength="16",
51     AllowedPattern="[a-zA-Z][a-zA-Z0-9]*",
52     ConstraintDescription=("must begin with a letter and contain only"
53                            " alphanumeric characters.")
54 ))
55 
56 dbpassword = t.add_parameter(Parameter(
57     "DBPassword",
58     NoEcho=True,
59     Description="The database admin account password",
60     Type="String",
61     MinLength="1",
62     MaxLength="41",
63     AllowedPattern="[a-zA-Z0-9]*",
64     ConstraintDescription="must contain only alphanumeric characters."
65 ))
66 
67 dbclass = t.add_parameter(Parameter(
68     "DBClass",
69     Default="db.m1.small",
70     Description="Database instance class",
71     Type="String",
72     AllowedValues=[
73         "db.m1.small", "db.m1.large", "db.m1.xlarge", "db.m2.xlarge",
74         "db.m2.2xlarge", "db.m2.4xlarge"],
75     ConstraintDescription="must select a valid database instance type.",
76 ))
77 
78 dballocatedstorage = t.add_parameter(Parameter(
79     "DBAllocatedStorage",
80     Default="5",
81     Description="The size of the database (Gb)",
82     Type="Number",
83     MinValue="5",
84     MaxValue="1024",
85     ConstraintDescription="must be between 5 and 1024Gb.",
86 ))
87 
88 
89 mydbsubnetgroup = t.add_resource(DBSubnetGroup(
90     "MyDBSubnetGroup",
91     DBSubnetGroupDescription="Subnets available for the RDS DB Instance",
92     SubnetIds=Ref(subnet),
93 ))
94 
95 myvpcsecuritygroup = t.add_resource(SecurityGroup(
96     "myVPCSecurityGroup",
97     GroupDescription="Security group for RDS DB Instance.",
98     VpcId=Ref(vpcid)
99 ))
100 
101 mydb = t.add_resource(DBInstance(
102     "MyDB",
103     DBName=Ref(dbname),
104     AllocatedStorage=Ref(dballocatedstorage),
105     DBInstanceClass=Ref(dbclass),
106     Engine="MySQL",
107     EngineVersion="5.5",
108     MasterUsername=Ref(dbuser),
109     MasterUserPassword=Ref(dbpassword),
110     DBSubnetGroupName=Ref(mydbsubnetgroup),
111     VPCSecurityGroups=[Ref(myvpcsecuritygroup)],
112 ))
113 
114 t.add_output(Output(
115     "JDBCConnectionString",
116     Description="JDBC connection string for database",
117     Value=Join("", [
118         "jdbc:mysql://",
119         GetAtt("MyDB", "Endpoint.Address"),
120         GetAtt("MyDB", "Endpoint.Port"),
121         "/",
122         Ref(dbname)
123     ])
124 ))
125 
126 print(t.to_json())
127
```
--- 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/examples/RDS_VPC.py b/examples/RDS_VPC.py
--- a/examples/RDS_VPC.py
+++ b/examples/RDS_VPC.py
@@ -70,8 +70,17 @@
     Description="Database instance class",
     Type="String",
     AllowedValues=[
-        "db.m1.small", "db.m1.large", "db.m1.xlarge", "db.m2.xlarge",
-        "db.m2.2xlarge", "db.m2.4xlarge"],
+      "db.m5.large", "db.m5.xlarge", "db.m5.2xlarge", "db.m5.4xlarge",
+      "db.m5.12xlarge", "db.m5.24xlarge", "db.m4.large", "db.m4.xlarge",
+      "db.m4.2xlarge", "db.m4.4xlarge", "db.m4.10xlarge", "db.m4.16xlarge",
+      "db.r4.large", "db.r4.xlarge", "db.r4.2xlarge", "db.r4.4xlarge",
+      "db.r4.8xlarge", "db.r4.16xlarge", "db.x1e.xlarge", "db.x1e.2xlarge",
+      "db.x1e.4xlarge", "db.x1e.8xlarge", "db.x1e.16xlarge", "db.x1e.32xlarge",
+      "db.x1.16xlarge", "db.x1.32xlarge", "db.r3.large", "db.r3.xlarge",
+      "db.r3.2xlarge", "db.r3.4xlarge", "db.r3.8xlarge", "db.t2.micro",
+      "db.t2.small", "db.t2.medium", "db.t2.large", "db.t2.xlarge",
+      "db.t2.2xlarge"
+    ],
     ConstraintDescription="must select a valid database instance type.",
 ))

{"golden_diff": "diff --git a/examples/RDS_VPC.py b/examples/RDS_VPC.py\n--- a/examples/RDS_VPC.py\n+++ b/examples/RDS_VPC.py\n@@ -70,8 +70,17 @@\n     Description=\"Database instance class\",\n     Type=\"String\",\n     AllowedValues=[\n-        \"db.m1.small\", \"db.m1.large\", \"db.m1.xlarge\", \"db.m2.xlarge\",\n-        \"db.m2.2xlarge\", \"db.m2.4xlarge\"],\n+      \"db.m5.large\", \"db.m5.xlarge\", \"db.m5.2xlarge\", \"db.m5.4xlarge\",\n+      \"db.m5.12xlarge\", \"db.m5.24xlarge\", \"db.m4.large\", \"db.m4.xlarge\",\n+      \"db.m4.2xlarge\", \"db.m4.4xlarge\", \"db.m4.10xlarge\", \"db.m4.16xlarge\",\n+      \"db.r4.large\", \"db.r4.xlarge\", \"db.r4.2xlarge\", \"db.r4.4xlarge\",\n+      \"db.r4.8xlarge\", \"db.r4.16xlarge\", \"db.x1e.xlarge\", \"db.x1e.2xlarge\",\n+      \"db.x1e.4xlarge\", \"db.x1e.8xlarge\", \"db.x1e.16xlarge\", \"db.x1e.32xlarge\",\n+      \"db.x1.16xlarge\", \"db.x1.32xlarge\", \"db.r3.large\", \"db.r3.xlarge\",\n+      \"db.r3.2xlarge\", \"db.r3.4xlarge\", \"db.r3.8xlarge\", \"db.t2.micro\",\n+      \"db.t2.small\", \"db.t2.medium\", \"db.t2.large\", \"db.t2.xlarge\",\n+      \"db.t2.2xlarge\"\n+    ],\n     ConstraintDescription=\"must select a valid database instance type.\",\n ))\n", "issue": "RDS VPC example instance classes are out of date\nhttps://github.com/cloudtools/troposphere/blob/565247a50bd27a8f45c3e408b466b193473cb9a6/examples/RDS_VPC.py#L67-L76\r\n\r\nThe current list of instance classes is documented here: https://aws.amazon.com/rds/instance-types/\n", "before_files": [{"content": "# Converted from RDS_VPC.template located at:\n# http://aws.amazon.com/cloudformation/aws-cloudformation-templates/\n\nfrom troposphere import GetAtt, Join, Output, Parameter, Ref, Template\nfrom troposphere.ec2 import SecurityGroup\nfrom troposphere.rds import DBInstance, DBSubnetGroup\n\n\nt = Template()\n\nt.add_description(\n    \"AWS CloudFormation Sample Template VPC_RDS_DB_Instance: Sample template \"\n    \"showing how to create an RDS DBInstance in an existing Virtual Private \"\n    \"Cloud (VPC). **WARNING** This template creates an Amazon Relational \"\n    \"Database Service database instance. You will be billed for the AWS \"\n    \"resources used if you create a stack from this template.\")\n\nvpcid = t.add_parameter(Parameter(\n    \"VpcId\",\n    Type=\"String\",\n    Description=\"VpcId of your existing Virtual Private Cloud (VPC)\"\n))\n\nsubnet = t.add_parameter(Parameter(\n    \"Subnets\",\n    Type=\"CommaDelimitedList\",\n    Description=(\n        \"The list of SubnetIds, for at least two Availability Zones in the \"\n        \"region in your Virtual Private Cloud (VPC)\")\n))\n\ndbname = t.add_parameter(Parameter(\n    \"DBName\",\n    Default=\"MyDatabase\",\n    Description=\"The database name\",\n    Type=\"String\",\n    MinLength=\"1\",\n    MaxLength=\"64\",\n    AllowedPattern=\"[a-zA-Z][a-zA-Z0-9]*\",\n    ConstraintDescription=(\"must begin with a letter and contain only\"\n                           \" alphanumeric characters.\")\n))\n\ndbuser = t.add_parameter(Parameter(\n    \"DBUser\",\n    NoEcho=True,\n    Description=\"The database admin account username\",\n    Type=\"String\",\n    MinLength=\"1\",\n    MaxLength=\"16\",\n    AllowedPattern=\"[a-zA-Z][a-zA-Z0-9]*\",\n    ConstraintDescription=(\"must begin with a letter and contain only\"\n                           \" alphanumeric characters.\")\n))\n\ndbpassword = t.add_parameter(Parameter(\n    \"DBPassword\",\n    NoEcho=True,\n    Description=\"The database admin account password\",\n    Type=\"String\",\n    MinLength=\"1\",\n    MaxLength=\"41\",\n    AllowedPattern=\"[a-zA-Z0-9]*\",\n    ConstraintDescription=\"must contain only alphanumeric characters.\"\n))\n\ndbclass = t.add_parameter(Parameter(\n    \"DBClass\",\n    Default=\"db.m1.small\",\n    Description=\"Database instance class\",\n    Type=\"String\",\n    AllowedValues=[\n        \"db.m1.small\", \"db.m1.large\", \"db.m1.xlarge\", \"db.m2.xlarge\",\n        \"db.m2.2xlarge\", \"db.m2.4xlarge\"],\n    ConstraintDescription=\"must select a valid database instance type.\",\n))\n\ndballocatedstorage = t.add_parameter(Parameter(\n    \"DBAllocatedStorage\",\n    Default=\"5\",\n    Description=\"The size of the database (Gb)\",\n    Type=\"Number\",\n    MinValue=\"5\",\n    MaxValue=\"1024\",\n    ConstraintDescription=\"must be between 5 and 1024Gb.\",\n))\n\n\nmydbsubnetgroup = t.add_resource(DBSubnetGroup(\n    \"MyDBSubnetGroup\",\n    DBSubnetGroupDescription=\"Subnets available for the RDS DB Instance\",\n    SubnetIds=Ref(subnet),\n))\n\nmyvpcsecuritygroup = t.add_resource(SecurityGroup(\n    \"myVPCSecurityGroup\",\n    GroupDescription=\"Security group for RDS DB Instance.\",\n    VpcId=Ref(vpcid)\n))\n\nmydb = t.add_resource(DBInstance(\n    \"MyDB\",\n    DBName=Ref(dbname),\n    AllocatedStorage=Ref(dballocatedstorage),\n    DBInstanceClass=Ref(dbclass),\n    Engine=\"MySQL\",\n    EngineVersion=\"5.5\",\n    MasterUsername=Ref(dbuser),\n    MasterUserPassword=Ref(dbpassword),\n    DBSubnetGroupName=Ref(mydbsubnetgroup),\n    VPCSecurityGroups=[Ref(myvpcsecuritygroup)],\n))\n\nt.add_output(Output(\n    \"JDBCConnectionString\",\n    Description=\"JDBC connection string for database\",\n    Value=Join(\"\", [\n        \"jdbc:mysql://\",\n        GetAtt(\"MyDB\", \"Endpoint.Address\"),\n        GetAtt(\"MyDB\", \"Endpoint.Port\"),\n        \"/\",\n        Ref(dbname)\n    ])\n))\n\nprint(t.to_json())\n", "path": "examples/RDS_VPC.py"}], "after_files": [{"content": "# Converted from RDS_VPC.template located at:\n# http://aws.amazon.com/cloudformation/aws-cloudformation-templates/\n\nfrom troposphere import GetAtt, Join, Output, Parameter, Ref, Template\nfrom troposphere.ec2 import SecurityGroup\nfrom troposphere.rds import DBInstance, DBSubnetGroup\n\n\nt = Template()\n\nt.add_description(\n    \"AWS CloudFormation Sample Template VPC_RDS_DB_Instance: Sample template \"\n    \"showing how to create an RDS DBInstance in an existing Virtual Private \"\n    \"Cloud (VPC). **WARNING** This template creates an Amazon Relational \"\n    \"Database Service database instance. You will be billed for the AWS \"\n    \"resources used if you create a stack from this template.\")\n\nvpcid = t.add_parameter(Parameter(\n    \"VpcId\",\n    Type=\"String\",\n    Description=\"VpcId of your existing Virtual Private Cloud (VPC)\"\n))\n\nsubnet = t.add_parameter(Parameter(\n    \"Subnets\",\n    Type=\"CommaDelimitedList\",\n    Description=(\n        \"The list of SubnetIds, for at least two Availability Zones in the \"\n        \"region in your Virtual Private Cloud (VPC)\")\n))\n\ndbname = t.add_parameter(Parameter(\n    \"DBName\",\n    Default=\"MyDatabase\",\n    Description=\"The database name\",\n    Type=\"String\",\n    MinLength=\"1\",\n    MaxLength=\"64\",\n    AllowedPattern=\"[a-zA-Z][a-zA-Z0-9]*\",\n    ConstraintDescription=(\"must begin with a letter and contain only\"\n                           \" alphanumeric characters.\")\n))\n\ndbuser = t.add_parameter(Parameter(\n    \"DBUser\",\n    NoEcho=True,\n    Description=\"The database admin account username\",\n    Type=\"String\",\n    MinLength=\"1\",\n    MaxLength=\"16\",\n    AllowedPattern=\"[a-zA-Z][a-zA-Z0-9]*\",\n    ConstraintDescription=(\"must begin with a letter and contain only\"\n                           \" alphanumeric characters.\")\n))\n\ndbpassword = t.add_parameter(Parameter(\n    \"DBPassword\",\n    NoEcho=True,\n    Description=\"The database admin account password\",\n    Type=\"String\",\n    MinLength=\"1\",\n    MaxLength=\"41\",\n    AllowedPattern=\"[a-zA-Z0-9]*\",\n    ConstraintDescription=\"must contain only alphanumeric characters.\"\n))\n\ndbclass = t.add_parameter(Parameter(\n    \"DBClass\",\n    Default=\"db.m1.small\",\n    Description=\"Database instance class\",\n    Type=\"String\",\n    AllowedValues=[\n      \"db.m5.large\", \"db.m5.xlarge\", \"db.m5.2xlarge\", \"db.m5.4xlarge\",\n      \"db.m5.12xlarge\", \"db.m5.24xlarge\", \"db.m4.large\", \"db.m4.xlarge\",\n      \"db.m4.2xlarge\", \"db.m4.4xlarge\", \"db.m4.10xlarge\", \"db.m4.16xlarge\",\n      \"db.r4.large\", \"db.r4.xlarge\", \"db.r4.2xlarge\", \"db.r4.4xlarge\",\n      \"db.r4.8xlarge\", \"db.r4.16xlarge\", \"db.x1e.xlarge\", \"db.x1e.2xlarge\",\n      \"db.x1e.4xlarge\", \"db.x1e.8xlarge\", \"db.x1e.16xlarge\", \"db.x1e.32xlarge\",\n      \"db.x1.16xlarge\", \"db.x1.32xlarge\", \"db.r3.large\", \"db.r3.xlarge\",\n      \"db.r3.2xlarge\", \"db.r3.4xlarge\", \"db.r3.8xlarge\", \"db.t2.micro\",\n      \"db.t2.small\", \"db.t2.medium\", \"db.t2.large\", \"db.t2.xlarge\",\n      \"db.t2.2xlarge\"\n    ],\n    ConstraintDescription=\"must select a valid database instance type.\",\n))\n\ndballocatedstorage = t.add_parameter(Parameter(\n    \"DBAllocatedStorage\",\n    Default=\"5\",\n    Description=\"The size of the database (Gb)\",\n    Type=\"Number\",\n    MinValue=\"5\",\n    MaxValue=\"1024\",\n    ConstraintDescription=\"must be between 5 and 1024Gb.\",\n))\n\n\nmydbsubnetgroup = t.add_resource(DBSubnetGroup(\n    \"MyDBSubnetGroup\",\n    DBSubnetGroupDescription=\"Subnets available for the RDS DB Instance\",\n    SubnetIds=Ref(subnet),\n))\n\nmyvpcsecuritygroup = t.add_resource(SecurityGroup(\n    \"myVPCSecurityGroup\",\n    GroupDescription=\"Security group for RDS DB Instance.\",\n    VpcId=Ref(vpcid)\n))\n\nmydb = t.add_resource(DBInstance(\n    \"MyDB\",\n    DBName=Ref(dbname),\n    AllocatedStorage=Ref(dballocatedstorage),\n    DBInstanceClass=Ref(dbclass),\n    Engine=\"MySQL\",\n    EngineVersion=\"5.5\",\n    MasterUsername=Ref(dbuser),\n    MasterUserPassword=Ref(dbpassword),\n    DBSubnetGroupName=Ref(mydbsubnetgroup),\n    VPCSecurityGroups=[Ref(myvpcsecuritygroup)],\n))\n\nt.add_output(Output(\n    \"JDBCConnectionString\",\n    Description=\"JDBC connection string for database\",\n    Value=Join(\"\", [\n        \"jdbc:mysql://\",\n        GetAtt(\"MyDB\", \"Endpoint.Address\"),\n        GetAtt(\"MyDB\", \"Endpoint.Port\"),\n        \"/\",\n        Ref(dbname)\n    ])\n))\n\nprint(t.to_json())\n", "path": "examples/RDS_VPC.py"}]}