We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Add a job for Python 3.9 to .travis.yml
It looks like Travis support specifying such a Python version as `3.9-dev`.

While I’m not sure we should officially support Python 3.9 it until its release, running tests on it will allow us to catch any issue early.

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `setup.py`
Content:
```
1 from os.path import dirname, join
2 from pkg_resources import parse_version
3 from setuptools import setup, find_packages, __version__ as setuptools_version
4 
5 
6 with open(join(dirname(__file__), 'scrapy/VERSION'), 'rb') as f:
7     version = f.read().decode('ascii').strip()
8 
9 
10 def has_environment_marker_platform_impl_support():
11     """Code extracted from 'pytest/setup.py'
12     https://github.com/pytest-dev/pytest/blob/7538680c/setup.py#L31
13 
14     The first known release to support environment marker with range operators
15     it is 18.5, see:
16     https://setuptools.readthedocs.io/en/latest/history.html#id235
17     """
18     return parse_version(setuptools_version) >= parse_version('18.5')
19 
20 
21 install_requires = [
22     'Twisted>=17.9.0',
23     'cryptography>=2.0',
24     'cssselect>=0.9.1',
25     'itemloaders>=1.0.1',
26     'parsel>=1.5.0',
27     'pyOpenSSL>=16.2.0',
28     'queuelib>=1.4.2',
29     'service_identity>=16.0.0',
30     'w3lib>=1.17.0',
31     'zope.interface>=4.1.3',
32     'protego>=0.1.15',
33     'itemadapter>=0.1.0',
34 ]
35 extras_require = {}
36 cpython_dependencies = [
37     'lxml>=3.5.0',
38     'PyDispatcher>=2.0.5',
39 ]
40 if has_environment_marker_platform_impl_support():
41     extras_require[':platform_python_implementation == "CPython"'] = cpython_dependencies
42     extras_require[':platform_python_implementation == "PyPy"'] = [
43         # Earlier lxml versions are affected by
44         # https://foss.heptapod.net/pypy/pypy/-/issues/2498,
45         # which was fixed in Cython 0.26, released on 2017-06-19, and used to
46         # generate the C headers of lxml release tarballs published since then, the
47         # first of which was:
48         'lxml>=4.0.0',
49         'PyPyDispatcher>=2.1.0',
50     ]
51 else:
52     install_requires.extend(cpython_dependencies)
53 
54 
55 setup(
56     name='Scrapy',
57     version=version,
58     url='https://scrapy.org',
59     project_urls={
60         'Documentation': 'https://docs.scrapy.org/',
61         'Source': 'https://github.com/scrapy/scrapy',
62         'Tracker': 'https://github.com/scrapy/scrapy/issues',
63     },
64     description='A high-level Web Crawling and Web Scraping framework',
65     long_description=open('README.rst').read(),
66     author='Scrapy developers',
67     maintainer='Pablo Hoffman',
68     maintainer_email='pablo@pablohoffman.com',
69     license='BSD',
70     packages=find_packages(exclude=('tests', 'tests.*')),
71     include_package_data=True,
72     zip_safe=False,
73     entry_points={
74         'console_scripts': ['scrapy = scrapy.cmdline:execute']
75     },
76     classifiers=[
77         'Framework :: Scrapy',
78         'Development Status :: 5 - Production/Stable',
79         'Environment :: Console',
80         'Intended Audience :: Developers',
81         'License :: OSI Approved :: BSD License',
82         'Operating System :: OS Independent',
83         'Programming Language :: Python',
84         'Programming Language :: Python :: 3',
85         'Programming Language :: Python :: 3.6',
86         'Programming Language :: Python :: 3.7',
87         'Programming Language :: Python :: 3.8',
88         'Programming Language :: Python :: Implementation :: CPython',
89         'Programming Language :: Python :: Implementation :: PyPy',
90         'Topic :: Internet :: WWW/HTTP',
91         'Topic :: Software Development :: Libraries :: Application Frameworks',
92         'Topic :: Software Development :: Libraries :: Python Modules',
93     ],
94     python_requires='>=3.6',
95     install_requires=install_requires,
96     extras_require=extras_require,
97 )
98
```
--- 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/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -85,6 +85,7 @@
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
         'Topic :: Internet :: WWW/HTTP',

{"golden_diff": "diff --git a/setup.py b/setup.py\n--- a/setup.py\n+++ b/setup.py\n@@ -85,6 +85,7 @@\n         'Programming Language :: Python :: 3.6',\n         'Programming Language :: Python :: 3.7',\n         'Programming Language :: Python :: 3.8',\n+        'Programming Language :: Python :: 3.9',\n         'Programming Language :: Python :: Implementation :: CPython',\n         'Programming Language :: Python :: Implementation :: PyPy',\n         'Topic :: Internet :: WWW/HTTP',\n", "issue": "Add a job for Python 3.9 to .travis.yml\nIt looks like Travis support specifying such a Python version as `3.9-dev`.\r\n\r\nWhile I\u2019m not sure we should officially support Python 3.9 it until its release, running tests on it will allow us to catch any issue early.\n", "before_files": [{"content": "from os.path import dirname, join\nfrom pkg_resources import parse_version\nfrom setuptools import setup, find_packages, __version__ as setuptools_version\n\n\nwith open(join(dirname(__file__), 'scrapy/VERSION'), 'rb') as f:\n    version = f.read().decode('ascii').strip()\n\n\ndef has_environment_marker_platform_impl_support():\n    \"\"\"Code extracted from 'pytest/setup.py'\n    https://github.com/pytest-dev/pytest/blob/7538680c/setup.py#L31\n\n    The first known release to support environment marker with range operators\n    it is 18.5, see:\n    https://setuptools.readthedocs.io/en/latest/history.html#id235\n    \"\"\"\n    return parse_version(setuptools_version) >= parse_version('18.5')\n\n\ninstall_requires = [\n    'Twisted>=17.9.0',\n    'cryptography>=2.0',\n    'cssselect>=0.9.1',\n    'itemloaders>=1.0.1',\n    'parsel>=1.5.0',\n    'pyOpenSSL>=16.2.0',\n    'queuelib>=1.4.2',\n    'service_identity>=16.0.0',\n    'w3lib>=1.17.0',\n    'zope.interface>=4.1.3',\n    'protego>=0.1.15',\n    'itemadapter>=0.1.0',\n]\nextras_require = {}\ncpython_dependencies = [\n    'lxml>=3.5.0',\n    'PyDispatcher>=2.0.5',\n]\nif has_environment_marker_platform_impl_support():\n    extras_require[':platform_python_implementation == \"CPython\"'] = cpython_dependencies\n    extras_require[':platform_python_implementation == \"PyPy\"'] = [\n        # Earlier lxml versions are affected by\n        # https://foss.heptapod.net/pypy/pypy/-/issues/2498,\n        # which was fixed in Cython 0.26, released on 2017-06-19, and used to\n        # generate the C headers of lxml release tarballs published since then, the\n        # first of which was:\n        'lxml>=4.0.0',\n        'PyPyDispatcher>=2.1.0',\n    ]\nelse:\n    install_requires.extend(cpython_dependencies)\n\n\nsetup(\n    name='Scrapy',\n    version=version,\n    url='https://scrapy.org',\n    project_urls={\n        'Documentation': 'https://docs.scrapy.org/',\n        'Source': 'https://github.com/scrapy/scrapy',\n        'Tracker': 'https://github.com/scrapy/scrapy/issues',\n    },\n    description='A high-level Web Crawling and Web Scraping framework',\n    long_description=open('README.rst').read(),\n    author='Scrapy developers',\n    maintainer='Pablo Hoffman',\n    maintainer_email='pablo@pablohoffman.com',\n    license='BSD',\n    packages=find_packages(exclude=('tests', 'tests.*')),\n    include_package_data=True,\n    zip_safe=False,\n    entry_points={\n        'console_scripts': ['scrapy = scrapy.cmdline:execute']\n    },\n    classifiers=[\n        'Framework :: Scrapy',\n        'Development Status :: 5 - Production/Stable',\n        'Environment :: Console',\n        'Intended Audience :: Developers',\n        'License :: OSI Approved :: BSD License',\n        'Operating System :: OS Independent',\n        'Programming Language :: Python',\n        'Programming Language :: Python :: 3',\n        'Programming Language :: Python :: 3.6',\n        'Programming Language :: Python :: 3.7',\n        'Programming Language :: Python :: 3.8',\n        'Programming Language :: Python :: Implementation :: CPython',\n        'Programming Language :: Python :: Implementation :: PyPy',\n        'Topic :: Internet :: WWW/HTTP',\n        'Topic :: Software Development :: Libraries :: Application Frameworks',\n        'Topic :: Software Development :: Libraries :: Python Modules',\n    ],\n    python_requires='>=3.6',\n    install_requires=install_requires,\n    extras_require=extras_require,\n)\n", "path": "setup.py"}], "after_files": [{"content": "from os.path import dirname, join\nfrom pkg_resources import parse_version\nfrom setuptools import setup, find_packages, __version__ as setuptools_version\n\n\nwith open(join(dirname(__file__), 'scrapy/VERSION'), 'rb') as f:\n    version = f.read().decode('ascii').strip()\n\n\ndef has_environment_marker_platform_impl_support():\n    \"\"\"Code extracted from 'pytest/setup.py'\n    https://github.com/pytest-dev/pytest/blob/7538680c/setup.py#L31\n\n    The first known release to support environment marker with range operators\n    it is 18.5, see:\n    https://setuptools.readthedocs.io/en/latest/history.html#id235\n    \"\"\"\n    return parse_version(setuptools_version) >= parse_version('18.5')\n\n\ninstall_requires = [\n    'Twisted>=17.9.0',\n    'cryptography>=2.0',\n    'cssselect>=0.9.1',\n    'itemloaders>=1.0.1',\n    'parsel>=1.5.0',\n    'pyOpenSSL>=16.2.0',\n    'queuelib>=1.4.2',\n    'service_identity>=16.0.0',\n    'w3lib>=1.17.0',\n    'zope.interface>=4.1.3',\n    'protego>=0.1.15',\n    'itemadapter>=0.1.0',\n]\nextras_require = {}\ncpython_dependencies = [\n    'lxml>=3.5.0',\n    'PyDispatcher>=2.0.5',\n]\nif has_environment_marker_platform_impl_support():\n    extras_require[':platform_python_implementation == \"CPython\"'] = cpython_dependencies\n    extras_require[':platform_python_implementation == \"PyPy\"'] = [\n        # Earlier lxml versions are affected by\n        # https://foss.heptapod.net/pypy/pypy/-/issues/2498,\n        # which was fixed in Cython 0.26, released on 2017-06-19, and used to\n        # generate the C headers of lxml release tarballs published since then, the\n        # first of which was:\n        'lxml>=4.0.0',\n        'PyPyDispatcher>=2.1.0',\n    ]\nelse:\n    install_requires.extend(cpython_dependencies)\n\n\nsetup(\n    name='Scrapy',\n    version=version,\n    url='https://scrapy.org',\n    project_urls={\n        'Documentation': 'https://docs.scrapy.org/',\n        'Source': 'https://github.com/scrapy/scrapy',\n        'Tracker': 'https://github.com/scrapy/scrapy/issues',\n    },\n    description='A high-level Web Crawling and Web Scraping framework',\n    long_description=open('README.rst').read(),\n    author='Scrapy developers',\n    maintainer='Pablo Hoffman',\n    maintainer_email='pablo@pablohoffman.com',\n    license='BSD',\n    packages=find_packages(exclude=('tests', 'tests.*')),\n    include_package_data=True,\n    zip_safe=False,\n    entry_points={\n        'console_scripts': ['scrapy = scrapy.cmdline:execute']\n    },\n    classifiers=[\n        'Framework :: Scrapy',\n        'Development Status :: 5 - Production/Stable',\n        'Environment :: Console',\n        'Intended Audience :: Developers',\n        'License :: OSI Approved :: BSD License',\n        'Operating System :: OS Independent',\n        'Programming Language :: Python',\n        'Programming Language :: Python :: 3',\n        'Programming Language :: Python :: 3.6',\n        'Programming Language :: Python :: 3.7',\n        'Programming Language :: Python :: 3.8',\n        'Programming Language :: Python :: 3.9',\n        'Programming Language :: Python :: Implementation :: CPython',\n        'Programming Language :: Python :: Implementation :: PyPy',\n        'Topic :: Internet :: WWW/HTTP',\n        'Topic :: Software Development :: Libraries :: Application Frameworks',\n        'Topic :: Software Development :: Libraries :: Python Modules',\n    ],\n    python_requires='>=3.6',\n    install_requires=install_requires,\n    extras_require=extras_require,\n)\n", "path": "setup.py"}]}