We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Fix documentation main page's header
The header is gone:
<img width="1032" alt="2018-10-03 0 18 01" src="https://user-images.githubusercontent.com/4660275/46377643-d0ce1080-c6a1-11e8-950b-d2d0c515dee1.png">


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `wemake_python_styleguide/visitors/ast/numbers.py`
Content:
```
1 # -*- coding: utf-8 -*-
2 
3 import ast
4 from typing import Optional
5 
6 from wemake_python_styleguide.constants import MAGIC_NUMBERS_WHITELIST
7 from wemake_python_styleguide.violations.best_practices import (
8     MagicNumberViolation,
9 )
10 from wemake_python_styleguide.visitors.base import BaseNodeVisitor
11 
12 
13 class MagicNumberVisitor(BaseNodeVisitor):
14     """Checks magic numbers used in the code."""
15 
16     _ALLOWED_PARENTS = (
17         ast.Assign,
18 
19         # Constructor usages:
20         ast.FunctionDef,
21         ast.arguments,
22 
23         # Primitives:
24         ast.List,
25         ast.Dict,
26         ast.Set,
27         ast.Tuple,
28     )
29 
30     _PROXY_PARENTS = (
31         ast.UnaryOp,
32     )
33 
34     def _get_real_parent(self, node: Optional[ast.AST]) -> Optional[ast.AST]:
35         """
36         Returns real number's parent.
37 
38         What can go wrong?
39 
40         1. Number can be negative: ``x = -1``,
41           so ``1`` has ``UnaryOp`` as parent, but should return ``Assign``
42 
43         """
44         parent = getattr(node, 'parent', None)
45         if isinstance(parent, self._PROXY_PARENTS):
46             return self._get_real_parent(parent)
47         return parent
48 
49     def _check_is_magic(self, node: ast.Num) -> None:
50         parent = self._get_real_parent(node)
51         if isinstance(parent, self._ALLOWED_PARENTS):
52             return
53 
54         if node.n in MAGIC_NUMBERS_WHITELIST:
55             return
56 
57         if isinstance(node.n, int) and node.n <= 10:
58             return
59 
60         self.add_violation(MagicNumberViolation(node, text=str(node.n)))
61 
62     def visit_Num(self, node: ast.Num) -> None:
63         """
64         Checks numbers not to be magic constants inside the code.
65 
66         Raises:
67             MagicNumberViolation
68 
69         """
70         self._check_is_magic(node)
71         self.generic_visit(node)
72
```
--- 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/wemake_python_styleguide/visitors/ast/numbers.py b/wemake_python_styleguide/visitors/ast/numbers.py
--- a/wemake_python_styleguide/visitors/ast/numbers.py
+++ b/wemake_python_styleguide/visitors/ast/numbers.py
@@ -27,6 +27,7 @@
         ast.Tuple,
     )
 
+    # TODO: make consistent naming rules for class attributes:
     _PROXY_PARENTS = (
         ast.UnaryOp,
     )

{"golden_diff": "diff --git a/wemake_python_styleguide/visitors/ast/numbers.py b/wemake_python_styleguide/visitors/ast/numbers.py\n--- a/wemake_python_styleguide/visitors/ast/numbers.py\n+++ b/wemake_python_styleguide/visitors/ast/numbers.py\n@@ -27,6 +27,7 @@\n         ast.Tuple,\n     )\n \n+    # TODO: make consistent naming rules for class attributes:\n     _PROXY_PARENTS = (\n         ast.UnaryOp,\n     )\n", "issue": "Fix documentation main page's header\nThe header is gone:\r\n<img width=\"1032\" alt=\"2018-10-03 0 18 01\" src=\"https://user-images.githubusercontent.com/4660275/46377643-d0ce1080-c6a1-11e8-950b-d2d0c515dee1.png\">\r\n\n", "before_files": [{"content": "# -*- coding: utf-8 -*-\n\nimport ast\nfrom typing import Optional\n\nfrom wemake_python_styleguide.constants import MAGIC_NUMBERS_WHITELIST\nfrom wemake_python_styleguide.violations.best_practices import (\n    MagicNumberViolation,\n)\nfrom wemake_python_styleguide.visitors.base import BaseNodeVisitor\n\n\nclass MagicNumberVisitor(BaseNodeVisitor):\n    \"\"\"Checks magic numbers used in the code.\"\"\"\n\n    _ALLOWED_PARENTS = (\n        ast.Assign,\n\n        # Constructor usages:\n        ast.FunctionDef,\n        ast.arguments,\n\n        # Primitives:\n        ast.List,\n        ast.Dict,\n        ast.Set,\n        ast.Tuple,\n    )\n\n    _PROXY_PARENTS = (\n        ast.UnaryOp,\n    )\n\n    def _get_real_parent(self, node: Optional[ast.AST]) -> Optional[ast.AST]:\n        \"\"\"\n        Returns real number's parent.\n\n        What can go wrong?\n\n        1. Number can be negative: ``x = -1``,\n          so ``1`` has ``UnaryOp`` as parent, but should return ``Assign``\n\n        \"\"\"\n        parent = getattr(node, 'parent', None)\n        if isinstance(parent, self._PROXY_PARENTS):\n            return self._get_real_parent(parent)\n        return parent\n\n    def _check_is_magic(self, node: ast.Num) -> None:\n        parent = self._get_real_parent(node)\n        if isinstance(parent, self._ALLOWED_PARENTS):\n            return\n\n        if node.n in MAGIC_NUMBERS_WHITELIST:\n            return\n\n        if isinstance(node.n, int) and node.n <= 10:\n            return\n\n        self.add_violation(MagicNumberViolation(node, text=str(node.n)))\n\n    def visit_Num(self, node: ast.Num) -> None:\n        \"\"\"\n        Checks numbers not to be magic constants inside the code.\n\n        Raises:\n            MagicNumberViolation\n\n        \"\"\"\n        self._check_is_magic(node)\n        self.generic_visit(node)\n", "path": "wemake_python_styleguide/visitors/ast/numbers.py"}], "after_files": [{"content": "# -*- coding: utf-8 -*-\n\nimport ast\nfrom typing import Optional\n\nfrom wemake_python_styleguide.constants import MAGIC_NUMBERS_WHITELIST\nfrom wemake_python_styleguide.violations.best_practices import (\n    MagicNumberViolation,\n)\nfrom wemake_python_styleguide.visitors.base import BaseNodeVisitor\n\n\nclass MagicNumberVisitor(BaseNodeVisitor):\n    \"\"\"Checks magic numbers used in the code.\"\"\"\n\n    _ALLOWED_PARENTS = (\n        ast.Assign,\n\n        # Constructor usages:\n        ast.FunctionDef,\n        ast.arguments,\n\n        # Primitives:\n        ast.List,\n        ast.Dict,\n        ast.Set,\n        ast.Tuple,\n    )\n\n    # TODO: make consistent naming rules for class attributes:\n    _PROXY_PARENTS = (\n        ast.UnaryOp,\n    )\n\n    def _get_real_parent(self, node: Optional[ast.AST]) -> Optional[ast.AST]:\n        \"\"\"\n        Returns real number's parent.\n\n        What can go wrong?\n\n        1. Number can be negative: ``x = -1``,\n          so ``1`` has ``UnaryOp`` as parent, but should return ``Assign``\n\n        \"\"\"\n        parent = getattr(node, 'parent', None)\n        if isinstance(parent, self._PROXY_PARENTS):\n            return self._get_real_parent(parent)\n        return parent\n\n    def _check_is_magic(self, node: ast.Num) -> None:\n        parent = self._get_real_parent(node)\n        if isinstance(parent, self._ALLOWED_PARENTS):\n            return\n\n        if node.n in MAGIC_NUMBERS_WHITELIST:\n            return\n\n        if isinstance(node.n, int) and node.n <= 10:\n            return\n\n        self.add_violation(MagicNumberViolation(node, text=str(node.n)))\n\n    def visit_Num(self, node: ast.Num) -> None:\n        \"\"\"\n        Checks numbers not to be magic constants inside the code.\n\n        Raises:\n            MagicNumberViolation\n\n        \"\"\"\n        self._check_is_magic(node)\n        self.generic_visit(node)\n", "path": "wemake_python_styleguide/visitors/ast/numbers.py"}]}