We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Most YAML documents use document starts (---)
Hi,

I am the creator of yamllint, the linter coala uses for YAML.

Since #965 was merged three months ago, coala fails on many projects like Ansible, OpenStack and even yamllint itself, because coala doesn't accept document start markers (`---`) anymore.

Document start markers are commonly used, and required when declaring multiple documents in a single `.yaml` file (see [the spec](http://yaml.org/spec/1.2/spec.html#id2800132)).

The proposed fix in the original issue (#923) was to disable the rule, but the implemented fix (#965) made document starts forbidden.

My opinion is that coala should either require document starts, or disable the rule by default.

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `bears/yaml/YAMLLintBear.py`
Content:
```
1 from coalib.bearlib.abstractions.Linter import linter
2 from dependency_management.requirements.PipRequirement import PipRequirement
3 import yaml
4 
5 
6 @linter(executable='yamllint',
7         output_format='regex',
8         output_regex=r'.+:(?P<line>\d+):(?P<column>\d+): '
9                      r'\[(?P<severity>error|warning)\] (?P<message>.+)')
10 class YAMLLintBear:
11     """
12     Check yaml code for errors and possible problems.
13 
14     You can read more about capabilities at
15     <http://yamllint.readthedocs.org/en/latest/rules.html>.
16     """
17 
18     LANGUAGES = {'YAML'}
19     REQUIREMENTS = {PipRequirement('yamllint', '1.5')}
20     AUTHORS = {'The coala developers'}
21     AUTHORS_EMAILS = {'coala-devel@googlegroups.com'}
22     LICENSE = 'AGPL-3.0'
23     CAN_DETECT = {'Syntax', 'Formatting'}
24 
25     @staticmethod
26     def generate_config(filename, file,
27                         document_start: bool=False):
28         """
29         :param document_start:
30             Use this rule to require or forbid the use of document start
31             marker (---).
32         """
33         yamllint_configs = {
34             'extends': 'default',
35             'rules': {
36                 'document-start': {
37                     'present': False
38                  }
39             }
40         }
41         if document_start:
42             yamllint_configs['rules']['document-start']['present'] = True
43 
44         return yaml.dump(yamllint_configs)
45 
46     @staticmethod
47     def create_arguments(filename, file, config_file, yamllint_config: str=''):
48         """
49         :param yamllint_config: Path to a custom configuration file.
50         """
51         args = ('-f', 'parsable', filename)
52         if yamllint_config:
53             args += ('--config-file=' + yamllint_config,)
54         else:
55             args += ('--config-file=' + config_file,)
56         return args
57
```
--- 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/bears/yaml/YAMLLintBear.py b/bears/yaml/YAMLLintBear.py
--- a/bears/yaml/YAMLLintBear.py
+++ b/bears/yaml/YAMLLintBear.py
@@ -24,7 +24,7 @@
 
     @staticmethod
     def generate_config(filename, file,
-                        document_start: bool=False):
+                        document_start: bool=None):
         """
         :param document_start:
             Use this rule to require or forbid the use of document start
@@ -33,13 +33,10 @@
         yamllint_configs = {
             'extends': 'default',
             'rules': {
-                'document-start': {
-                    'present': False
-                 }
-            }
+                'document-start': 'disable' if document_start is None
+                                  else {'present': document_start},
+            },
         }
-        if document_start:
-            yamllint_configs['rules']['document-start']['present'] = True
 
         return yaml.dump(yamllint_configs)

{"golden_diff": "diff --git a/bears/yaml/YAMLLintBear.py b/bears/yaml/YAMLLintBear.py\n--- a/bears/yaml/YAMLLintBear.py\n+++ b/bears/yaml/YAMLLintBear.py\n@@ -24,7 +24,7 @@\n \n     @staticmethod\n     def generate_config(filename, file,\n-                        document_start: bool=False):\n+                        document_start: bool=None):\n         \"\"\"\n         :param document_start:\n             Use this rule to require or forbid the use of document start\n@@ -33,13 +33,10 @@\n         yamllint_configs = {\n             'extends': 'default',\n             'rules': {\n-                'document-start': {\n-                    'present': False\n-                 }\n-            }\n+                'document-start': 'disable' if document_start is None\n+                                  else {'present': document_start},\n+            },\n         }\n-        if document_start:\n-            yamllint_configs['rules']['document-start']['present'] = True\n \n         return yaml.dump(yamllint_configs)\n", "issue": "Most YAML documents use document starts (---)\nHi,\r\n\r\nI am the creator of yamllint, the linter coala uses for YAML.\r\n\r\nSince #965 was merged three months ago, coala fails on many projects like Ansible, OpenStack and even yamllint itself, because coala doesn't accept document start markers (`---`) anymore.\r\n\r\nDocument start markers are commonly used, and required when declaring multiple documents in a single `.yaml` file (see [the spec](http://yaml.org/spec/1.2/spec.html#id2800132)).\r\n\r\nThe proposed fix in the original issue (#923) was to disable the rule, but the implemented fix (#965) made document starts forbidden.\r\n\r\nMy opinion is that coala should either require document starts, or disable the rule by default.\n", "before_files": [{"content": "from coalib.bearlib.abstractions.Linter import linter\nfrom dependency_management.requirements.PipRequirement import PipRequirement\nimport yaml\n\n\n@linter(executable='yamllint',\n        output_format='regex',\n        output_regex=r'.+:(?P<line>\\d+):(?P<column>\\d+): '\n                     r'\\[(?P<severity>error|warning)\\] (?P<message>.+)')\nclass YAMLLintBear:\n    \"\"\"\n    Check yaml code for errors and possible problems.\n\n    You can read more about capabilities at\n    <http://yamllint.readthedocs.org/en/latest/rules.html>.\n    \"\"\"\n\n    LANGUAGES = {'YAML'}\n    REQUIREMENTS = {PipRequirement('yamllint', '1.5')}\n    AUTHORS = {'The coala developers'}\n    AUTHORS_EMAILS = {'coala-devel@googlegroups.com'}\n    LICENSE = 'AGPL-3.0'\n    CAN_DETECT = {'Syntax', 'Formatting'}\n\n    @staticmethod\n    def generate_config(filename, file,\n                        document_start: bool=False):\n        \"\"\"\n        :param document_start:\n            Use this rule to require or forbid the use of document start\n            marker (---).\n        \"\"\"\n        yamllint_configs = {\n            'extends': 'default',\n            'rules': {\n                'document-start': {\n                    'present': False\n                 }\n            }\n        }\n        if document_start:\n            yamllint_configs['rules']['document-start']['present'] = True\n\n        return yaml.dump(yamllint_configs)\n\n    @staticmethod\n    def create_arguments(filename, file, config_file, yamllint_config: str=''):\n        \"\"\"\n        :param yamllint_config: Path to a custom configuration file.\n        \"\"\"\n        args = ('-f', 'parsable', filename)\n        if yamllint_config:\n            args += ('--config-file=' + yamllint_config,)\n        else:\n            args += ('--config-file=' + config_file,)\n        return args\n", "path": "bears/yaml/YAMLLintBear.py"}], "after_files": [{"content": "from coalib.bearlib.abstractions.Linter import linter\nfrom dependency_management.requirements.PipRequirement import PipRequirement\nimport yaml\n\n\n@linter(executable='yamllint',\n        output_format='regex',\n        output_regex=r'.+:(?P<line>\\d+):(?P<column>\\d+): '\n                     r'\\[(?P<severity>error|warning)\\] (?P<message>.+)')\nclass YAMLLintBear:\n    \"\"\"\n    Check yaml code for errors and possible problems.\n\n    You can read more about capabilities at\n    <http://yamllint.readthedocs.org/en/latest/rules.html>.\n    \"\"\"\n\n    LANGUAGES = {'YAML'}\n    REQUIREMENTS = {PipRequirement('yamllint', '1.5')}\n    AUTHORS = {'The coala developers'}\n    AUTHORS_EMAILS = {'coala-devel@googlegroups.com'}\n    LICENSE = 'AGPL-3.0'\n    CAN_DETECT = {'Syntax', 'Formatting'}\n\n    @staticmethod\n    def generate_config(filename, file,\n                        document_start: bool=None):\n        \"\"\"\n        :param document_start:\n            Use this rule to require or forbid the use of document start\n            marker (---).\n        \"\"\"\n        yamllint_configs = {\n            'extends': 'default',\n            'rules': {\n                'document-start': 'disable' if document_start is None\n                                  else {'present': document_start},\n            },\n        }\n\n        return yaml.dump(yamllint_configs)\n\n    @staticmethod\n    def create_arguments(filename, file, config_file, yamllint_config: str=''):\n        \"\"\"\n        :param yamllint_config: Path to a custom configuration file.\n        \"\"\"\n        args = ('-f', 'parsable', filename)\n        if yamllint_config:\n            args += ('--config-file=' + yamllint_config,)\n        else:\n            args += ('--config-file=' + config_file,)\n        return args\n", "path": "bears/yaml/YAMLLintBear.py"}]}