We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
ModuleNotFoundError: No module named 'plasmapy.classes' on plasmapy import
On importing freshly installed plasmapy into a new environment:

    (plasmapy) [~]$ python
    Python 3.6.2 |Continuum Analytics, Inc.| (default, Jul 20 2017, 13:51:32) 
    [GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import plasmapy
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/home/dominik/.anaconda3/envs/plasmapy/lib/python3.6/site-packages/plasmapy/__init__.py", line 8, in <module>
        from .classes import Plasma
    ModuleNotFoundError: No module named 'plasmapy.classes'

The goal of this one is being able to import plasmapy. At all.

The issue likely lies in `plasmapy/__init__.py`. 

To quote @cadair 's words of encouragement on this bugfixing journey, *packaging is a special kind of hell*. 

--- 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 setuptools import setup
2 
3 
4 # Package metadata
5 metadata = {}
6 with open('plasmapy/_metadata.py', 'r') as metadata_file:
7     exec(metadata_file.read(), metadata)
8 
9 # Requirements
10 with open('requirements/base.txt', 'r') as req_file:
11     requirements = req_file.read().splitlines()
12 
13 setup(name=metadata['name'],
14       version=metadata['version'],
15       description="Python package for plasma physics",
16       requires=requirements,
17       install_requires=requirements,
18       provides=[metadata['name']],
19       author=metadata['author'],
20       author_email="namurphy@cfa.harvard.edu",  # until we get an email address
21       license="BSD",
22       url="https://github.com/PlasmaPy/PlasmaPy",  # until we make a webpage
23       long_description=metadata['description'],
24       keywords=['plasma', 'plasma physics', 'science'],
25       classifiers=[
26         'Intended Audience :: Science/Research',
27         'License :: OSI Approved :: BSD License',
28         'Operating System :: OS Independent',
29         'Programming Language :: Python :: 3 :: Only',
30         'Programming Language :: Python :: 3.6',
31         'Topic :: Scientific/Engineering :: Physics',
32         'Topic :: Scientific/Engineering :: Astronomy',
33         'Development Status :: 2 - Pre-Alpha',
34         ],
35       packages=["plasmapy"],
36       zip_safe=False,
37       use_2to3=False,
38       python_requires='>=3.6',
39       )
40
```
--- 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
@@ -1,4 +1,4 @@
-from setuptools import setup
+from setuptools import setup, find_packages
 
 
 # Package metadata
@@ -32,7 +32,7 @@
         'Topic :: Scientific/Engineering :: Astronomy',
         'Development Status :: 2 - Pre-Alpha',
         ],
-      packages=["plasmapy"],
+      packages=find_packages(),
       zip_safe=False,
       use_2to3=False,
       python_requires='>=3.6',

{"golden_diff": "diff --git a/setup.py b/setup.py\n--- a/setup.py\n+++ b/setup.py\n@@ -1,4 +1,4 @@\n-from setuptools import setup\n+from setuptools import setup, find_packages\n \n \n # Package metadata\n@@ -32,7 +32,7 @@\n         'Topic :: Scientific/Engineering :: Astronomy',\n         'Development Status :: 2 - Pre-Alpha',\n         ],\n-      packages=[\"plasmapy\"],\n+      packages=find_packages(),\n       zip_safe=False,\n       use_2to3=False,\n       python_requires='>=3.6',\n", "issue": "ModuleNotFoundError: No module named 'plasmapy.classes' on plasmapy import\nOn importing freshly installed plasmapy into a new environment:\r\n\r\n    (plasmapy) [~]$ python\r\n    Python 3.6.2 |Continuum Analytics, Inc.| (default, Jul 20 2017, 13:51:32) \r\n    [GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux\r\n    Type \"help\", \"copyright\", \"credits\" or \"license\" for more information.\r\n    >>> import plasmapy\r\n    Traceback (most recent call last):\r\n      File \"<stdin>\", line 1, in <module>\r\n      File \"/home/dominik/.anaconda3/envs/plasmapy/lib/python3.6/site-packages/plasmapy/__init__.py\", line 8, in <module>\r\n        from .classes import Plasma\r\n    ModuleNotFoundError: No module named 'plasmapy.classes'\r\n\r\nThe goal of this one is being able to import plasmapy. At all.\r\n\r\nThe issue likely lies in `plasmapy/__init__.py`. \r\n\r\nTo quote @cadair 's words of encouragement on this bugfixing journey, *packaging is a special kind of hell*. \n", "before_files": [{"content": "from setuptools import setup\n\n\n# Package metadata\nmetadata = {}\nwith open('plasmapy/_metadata.py', 'r') as metadata_file:\n    exec(metadata_file.read(), metadata)\n\n# Requirements\nwith open('requirements/base.txt', 'r') as req_file:\n    requirements = req_file.read().splitlines()\n\nsetup(name=metadata['name'],\n      version=metadata['version'],\n      description=\"Python package for plasma physics\",\n      requires=requirements,\n      install_requires=requirements,\n      provides=[metadata['name']],\n      author=metadata['author'],\n      author_email=\"namurphy@cfa.harvard.edu\",  # until we get an email address\n      license=\"BSD\",\n      url=\"https://github.com/PlasmaPy/PlasmaPy\",  # until we make a webpage\n      long_description=metadata['description'],\n      keywords=['plasma', 'plasma physics', 'science'],\n      classifiers=[\n        'Intended Audience :: Science/Research',\n        'License :: OSI Approved :: BSD License',\n        'Operating System :: OS Independent',\n        'Programming Language :: Python :: 3 :: Only',\n        'Programming Language :: Python :: 3.6',\n        'Topic :: Scientific/Engineering :: Physics',\n        'Topic :: Scientific/Engineering :: Astronomy',\n        'Development Status :: 2 - Pre-Alpha',\n        ],\n      packages=[\"plasmapy\"],\n      zip_safe=False,\n      use_2to3=False,\n      python_requires='>=3.6',\n      )\n", "path": "setup.py"}], "after_files": [{"content": "from setuptools import setup, find_packages\n\n\n# Package metadata\nmetadata = {}\nwith open('plasmapy/_metadata.py', 'r') as metadata_file:\n    exec(metadata_file.read(), metadata)\n\n# Requirements\nwith open('requirements/base.txt', 'r') as req_file:\n    requirements = req_file.read().splitlines()\n\nsetup(name=metadata['name'],\n      version=metadata['version'],\n      description=\"Python package for plasma physics\",\n      requires=requirements,\n      install_requires=requirements,\n      provides=[metadata['name']],\n      author=metadata['author'],\n      author_email=\"namurphy@cfa.harvard.edu\",  # until we get an email address\n      license=\"BSD\",\n      url=\"https://github.com/PlasmaPy/PlasmaPy\",  # until we make a webpage\n      long_description=metadata['description'],\n      keywords=['plasma', 'plasma physics', 'science'],\n      classifiers=[\n        'Intended Audience :: Science/Research',\n        'License :: OSI Approved :: BSD License',\n        'Operating System :: OS Independent',\n        'Programming Language :: Python :: 3 :: Only',\n        'Programming Language :: Python :: 3.6',\n        'Topic :: Scientific/Engineering :: Physics',\n        'Topic :: Scientific/Engineering :: Astronomy',\n        'Development Status :: 2 - Pre-Alpha',\n        ],\n      packages=find_packages(),\n      zip_safe=False,\n      use_2to3=False,\n      python_requires='>=3.6',\n      )\n", "path": "setup.py"}]}