prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  [DOC] Clarify Python version requirements
  # Brief Description of Fix
  
  I was looking through documentation (for users and contributors), and it was unclear to me which python versions we actually support. It seems that we support python 3.6 + 3.7. This arose as I was updating the `pyproject.toml` file to avoid the warning:
  ```
  --py36 is deprecated and will be removed in a future version. Use --target-version py36 instead.
  ```
  
  Our current locations of explicit python versions are in:
  - `pyproject.toml`
      - `py36 = true`
  - `environment-dev.yml`
      - `- python >= 3.6`
  - `.azure-pipelines/pipeline-master.yml`
      - `python.version: "3.7"`
  
  # Proposed Fix
  
  If `pyjanitor` is in fact meant to function on 3.6+, we should
  - Explicitly inform contributors that their code should be 3.6+ compatible
  - Inform users which python versions the package requires, on the documentation site, PyPI etc
  - Add `python_requires=">=3.6"` to `setup.py`
  
  
  --- 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 def requirements():
  5     with open("requirements.txt", "r+") as f:
  6         return f.read()
  7 
  8 
  9 setup(
  10     name="pyjanitor",
  11     version="0.18.0",
  12     description="Tools for cleaning pandas DataFrames",
  13     author="Eric J. Ma",
  14     author_email="ericmajinglong@gmail.com",
  15     url="https://github.com/ericmjl/pyjanitor",
  16     packages=["janitor"],
  17     install_requires=requirements(),
  18 )
  19
  ```
  --- 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()
  
  ```
  
golden_diff: diff --git a/setup.py b/setup.py
  --- a/setup.py
  +++ b/setup.py
  @@ -15,4 +15,5 @@
       url="https://github.com/ericmjl/pyjanitor",
       packages=["janitor"],
       install_requires=requirements(),
  +    python_requires=">=3.6",
   )
  
verification_info: {"golden_diff": "diff --git a/setup.py b/setup.py\n--- a/setup.py\n+++ b/setup.py\n@@ -15,4 +15,5 @@\n     url=\"https://github.com/ericmjl/pyjanitor\",\n     packages=[\"janitor\"],\n     install_requires=requirements(),\n+    python_requires=\">=3.6\",\n )\n", "issue": "[DOC] Clarify Python version requirements\n# Brief Description of Fix\r\n\r\nI was looking through documentation (for users and contributors), and it was unclear to me which python versions we actually support. It seems that we support python 3.6 + 3.7. This arose as I was updating the `pyproject.toml` file to avoid the warning:\r\n```\r\n--py36 is deprecated and will be removed in a future version. Use --target-version py36 instead.\r\n```\r\n\r\nOur current locations of explicit python versions are in:\r\n- `pyproject.toml`\r\n    - `py36 = true`\r\n- `environment-dev.yml`\r\n    - `- python >= 3.6`\r\n- `.azure-pipelines/pipeline-master.yml`\r\n    - `python.version: \"3.7\"`\r\n\r\n# Proposed Fix\r\n\r\nIf `pyjanitor` is in fact meant to function on 3.6+, we should\r\n- Explicitly inform contributors that their code should be 3.6+ compatible\r\n- Inform users which python versions the package requires, on the documentation site, PyPI etc\r\n- Add `python_requires=\">=3.6\"` to `setup.py`\r\n\n", "before_files": [{"content": "from setuptools import setup\n\n\ndef requirements():\n    with open(\"requirements.txt\", \"r+\") as f:\n        return f.read()\n\n\nsetup(\n    name=\"pyjanitor\",\n    version=\"0.18.0\",\n    description=\"Tools for cleaning pandas DataFrames\",\n    author=\"Eric J. Ma\",\n    author_email=\"ericmajinglong@gmail.com\",\n    url=\"https://github.com/ericmjl/pyjanitor\",\n    packages=[\"janitor\"],\n    install_requires=requirements(),\n)\n", "path": "setup.py"}], "after_files": [{"content": "from setuptools import setup\n\n\ndef requirements():\n    with open(\"requirements.txt\", \"r+\") as f:\n        return f.read()\n\n\nsetup(\n    name=\"pyjanitor\",\n    version=\"0.18.0\",\n    description=\"Tools for cleaning pandas DataFrames\",\n    author=\"Eric J. Ma\",\n    author_email=\"ericmajinglong@gmail.com\",\n    url=\"https://github.com/ericmjl/pyjanitor\",\n    packages=[\"janitor\"],\n    install_requires=requirements(),\n    python_requires=\">=3.6\",\n)\n", "path": "setup.py"}]}