We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Drop Python 2.6 support
For the most relevant discussion about the topic, see #1294.

Plan:
1. In the upcoming minor release, I'm going to include `warnings.warn(msg, DeprecationWarning)`. with the message saying "Python v2.6 support is deprecated and is going to be dropped entirely in the upcoming v0.11.0 release. Update your Python version if you want to have access to the latest features and bug fixes in MongoEngine."
2. In v0.11.0 (most likely shipped with #1428), I'll update the way we do dict comprehensions and other relics of the past, thus making it truly incompatible with v2.6.

Cc @lafrech @gukoff 

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `mongoengine/python_support.py`
Content:
```
1 """Helper functions and types to aid with Python 2.5 - 3 support."""
2 
3 import sys
4 import pymongo
5 
6 
7 if pymongo.version_tuple[0] < 3:
8     IS_PYMONGO_3 = False
9 else:
10     IS_PYMONGO_3 = True
11 
12 PY3 = sys.version_info[0] == 3
13 
14 if PY3:
15     import codecs
16     from io import BytesIO as StringIO
17 
18     # return s converted to binary.  b('test') should be equivalent to b'test'
19     def b(s):
20         return codecs.latin_1_encode(s)[0]
21 
22     bin_type = bytes
23     txt_type = str
24 else:
25     try:
26         from cStringIO import StringIO
27     except ImportError:
28         from StringIO import StringIO
29 
30     # Conversion to binary only necessary in Python 3
31     def b(s):
32         return s
33 
34     bin_type = str
35     txt_type = unicode
36 
37 str_types = (bin_type, txt_type)
38
```
--- 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/mongoengine/python_support.py b/mongoengine/python_support.py
--- a/mongoengine/python_support.py
+++ b/mongoengine/python_support.py
@@ -1,9 +1,22 @@
-"""Helper functions and types to aid with Python 2.5 - 3 support."""
+"""Helper functions and types to aid with Python 2.6 - 3 support."""
 
 import sys
+import warnings
+
 import pymongo
 
 
+# Show a deprecation warning for people using Python v2.6
+# TODO remove in mongoengine v0.11.0
+if sys.version_info[0] == 2 and sys.version_info[1] == 6:
+    warnings.warn(
+        'Python v2.6 support is deprecated and is going to be dropped '
+        'entirely in the upcoming v0.11.0 release. Update your Python '
+        'version if you want to have access to the latest features and '
+        'bug fixes in MongoEngine.',
+        DeprecationWarning
+    )
+
 if pymongo.version_tuple[0] < 3:
     IS_PYMONGO_3 = False
 else:

{"golden_diff": "diff --git a/mongoengine/python_support.py b/mongoengine/python_support.py\n--- a/mongoengine/python_support.py\n+++ b/mongoengine/python_support.py\n@@ -1,9 +1,22 @@\n-\"\"\"Helper functions and types to aid with Python 2.5 - 3 support.\"\"\"\n+\"\"\"Helper functions and types to aid with Python 2.6 - 3 support.\"\"\"\n \n import sys\n+import warnings\n+\n import pymongo\n \n \n+# Show a deprecation warning for people using Python v2.6\n+# TODO remove in mongoengine v0.11.0\n+if sys.version_info[0] == 2 and sys.version_info[1] == 6:\n+    warnings.warn(\n+        'Python v2.6 support is deprecated and is going to be dropped '\n+        'entirely in the upcoming v0.11.0 release. Update your Python '\n+        'version if you want to have access to the latest features and '\n+        'bug fixes in MongoEngine.',\n+        DeprecationWarning\n+    )\n+\n if pymongo.version_tuple[0] < 3:\n     IS_PYMONGO_3 = False\n else:\n", "issue": "Drop Python 2.6 support\nFor the most relevant discussion about the topic, see #1294.\r\n\r\nPlan:\r\n1. In the upcoming minor release, I'm going to include `warnings.warn(msg, DeprecationWarning)`. with the message saying \"Python v2.6 support is deprecated and is going to be dropped entirely in the upcoming v0.11.0 release. Update your Python version if you want to have access to the latest features and bug fixes in MongoEngine.\"\r\n2. In v0.11.0 (most likely shipped with #1428), I'll update the way we do dict comprehensions and other relics of the past, thus making it truly incompatible with v2.6.\r\n\r\nCc @lafrech @gukoff \n", "before_files": [{"content": "\"\"\"Helper functions and types to aid with Python 2.5 - 3 support.\"\"\"\n\nimport sys\nimport pymongo\n\n\nif pymongo.version_tuple[0] < 3:\n    IS_PYMONGO_3 = False\nelse:\n    IS_PYMONGO_3 = True\n\nPY3 = sys.version_info[0] == 3\n\nif PY3:\n    import codecs\n    from io import BytesIO as StringIO\n\n    # return s converted to binary.  b('test') should be equivalent to b'test'\n    def b(s):\n        return codecs.latin_1_encode(s)[0]\n\n    bin_type = bytes\n    txt_type = str\nelse:\n    try:\n        from cStringIO import StringIO\n    except ImportError:\n        from StringIO import StringIO\n\n    # Conversion to binary only necessary in Python 3\n    def b(s):\n        return s\n\n    bin_type = str\n    txt_type = unicode\n\nstr_types = (bin_type, txt_type)\n", "path": "mongoengine/python_support.py"}], "after_files": [{"content": "\"\"\"Helper functions and types to aid with Python 2.6 - 3 support.\"\"\"\n\nimport sys\nimport warnings\n\nimport pymongo\n\n\n# Show a deprecation warning for people using Python v2.6\n# TODO remove in mongoengine v0.11.0\nif sys.version_info[0] == 2 and sys.version_info[1] == 6:\n    warnings.warn(\n        'Python v2.6 support is deprecated and is going to be dropped '\n        'entirely in the upcoming v0.11.0 release. Update your Python '\n        'version if you want to have access to the latest features and '\n        'bug fixes in MongoEngine.',\n        DeprecationWarning\n    )\n\nif pymongo.version_tuple[0] < 3:\n    IS_PYMONGO_3 = False\nelse:\n    IS_PYMONGO_3 = True\n\nPY3 = sys.version_info[0] == 3\n\nif PY3:\n    import codecs\n    from io import BytesIO as StringIO\n\n    # return s converted to binary.  b('test') should be equivalent to b'test'\n    def b(s):\n        return codecs.latin_1_encode(s)[0]\n\n    bin_type = bytes\n    txt_type = str\nelse:\n    try:\n        from cStringIO import StringIO\n    except ImportError:\n        from StringIO import StringIO\n\n    # Conversion to binary only necessary in Python 3\n    def b(s):\n        return s\n\n    bin_type = str\n    txt_type = unicode\n\nstr_types = (bin_type, txt_type)\n", "path": "mongoengine/python_support.py"}]}