prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  [INF] Make requirements.txt smaller
  Follow-up from #257 
  
  The idea is to have feature-specific requirements.txt. Such as for biology, specifically requires biopython.
  
  so we can install the package per feature as needed, such as with extra biology. It goes `pip install "pyjanitor[biology]"`
  
  The example of such implementations in `setup.py` is available at this link: https://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-extras-optional-features-with-their-own-dependencies
  [INF] Make requirements.txt smaller
  Follow-up from #257 
  
  The idea is to have feature-specific requirements.txt. Such as for biology, specifically requires biopython.
  
  so we can install the package per feature as needed, such as with extra biology. It goes `pip install "pyjanitor[biology]"`
  
  The example of such implementations in `setup.py` is available at this link: https://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-extras-optional-features-with-their-own-dependencies
  
  </issue>
  <code>
  [start of setup.py]
  1 import re
  2 from pathlib import Path
  3 
  4 from setuptools import setup
  5 
  6 
  7 def requirements():
  8     with open("requirements.txt", "r+") as f:
  9         return f.read()
  10 
  11 
  12 def generate_long_description() -> str:
  13     """
  14     Extra chunks from README for PyPI description.
  15 
  16     Target chunks must be contained within `.. pypi-doc` pair comments,
  17     so there must be an even number of comments in README.
  18 
  19     :returns: Extracted description from README
  20 
  21     """
  22     # Read the contents of README file
  23     this_directory = Path(__file__).parent
  24     with open(this_directory / "README.rst", encoding="utf-8") as f:
  25         readme = f.read()
  26 
  27     # Find pypi-doc comments in README
  28     indices = [m.start() for m in re.finditer(".. pypi-doc", readme)]
  29     if len(indices) % 2 != 0:
  30         raise Exception("Odd number of `.. pypi-doc` comments in README")
  31 
  32     # Loop through pairs of comments and save text between pairs
  33     long_description = ""
  34     for i in range(0, len(indices), 2):
  35         start_index = indices[i] + 11
  36         end_index = indices[i + 1]
  37         long_description += readme[start_index:end_index]
  38     return long_description
  39 
  40 
  41 setup(
  42     name="pyjanitor",
  43     version="0.18.2",
  44     description="Tools for cleaning pandas DataFrames",
  45     author="Eric J. Ma",
  46     author_email="ericmajinglong@gmail.com",
  47     url="https://github.com/ericmjl/pyjanitor",
  48     packages=["janitor"],
  49     install_requires=requirements(),
  50     python_requires=">=3.6",
  51     long_description=generate_long_description(),
  52     long_description_content_type="text/x-rst",
  53 )
  54
  [end of setup.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/setup.py b/setup.py
  --- a/setup.py
  +++ b/setup.py
  @@ -38,6 +38,12 @@
       return long_description
   
   
  +extra_spark = ["pyspark"]
  +extra_biology = ["biopython"]
  +extra_chemistry = ["rdkit"]
  +extra_engineering = ["unyt"]
  +extra_all = extra_biology + extra_engineering + extra_spark
  +
   setup(
       name="pyjanitor",
       version="0.18.2",
  @@ -47,6 +53,14 @@
       url="https://github.com/ericmjl/pyjanitor",
       packages=["janitor"],
       install_requires=requirements(),
  +    extras_require={
  +        "all": extra_all,
  +        "biology": extra_biology,
  +        # "chemistry": extra_chemistry, should be inserted once rdkit
  +        # fixes https://github.com/rdkit/rdkit/issues/1812
  +        "engineering": extra_engineering,
  +        "spark": extra_spark,
  +    },
       python_requires=">=3.6",
       long_description=generate_long_description(),
       long_description_content_type="text/x-rst",
  
verification_info: {"golden_diff": "diff --git a/setup.py b/setup.py\n--- a/setup.py\n+++ b/setup.py\n@@ -38,6 +38,12 @@\n     return long_description\n \n \n+extra_spark = [\"pyspark\"]\n+extra_biology = [\"biopython\"]\n+extra_chemistry = [\"rdkit\"]\n+extra_engineering = [\"unyt\"]\n+extra_all = extra_biology + extra_engineering + extra_spark\n+\n setup(\n     name=\"pyjanitor\",\n     version=\"0.18.2\",\n@@ -47,6 +53,14 @@\n     url=\"https://github.com/ericmjl/pyjanitor\",\n     packages=[\"janitor\"],\n     install_requires=requirements(),\n+    extras_require={\n+        \"all\": extra_all,\n+        \"biology\": extra_biology,\n+        # \"chemistry\": extra_chemistry, should be inserted once rdkit\n+        # fixes https://github.com/rdkit/rdkit/issues/1812\n+        \"engineering\": extra_engineering,\n+        \"spark\": extra_spark,\n+    },\n     python_requires=\">=3.6\",\n     long_description=generate_long_description(),\n     long_description_content_type=\"text/x-rst\",\n", "issue": "[INF] Make requirements.txt smaller\nFollow-up from #257 \r\n\r\nThe idea is to have feature-specific requirements.txt. Such as for biology, specifically requires biopython.\r\n\r\nso we can install the package per feature as needed, such as with extra biology. It goes `pip install \"pyjanitor[biology]\"`\r\n\r\nThe example of such implementations in `setup.py` is available at this link: https://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-extras-optional-features-with-their-own-dependencies\n[INF] Make requirements.txt smaller\nFollow-up from #257 \r\n\r\nThe idea is to have feature-specific requirements.txt. Such as for biology, specifically requires biopython.\r\n\r\nso we can install the package per feature as needed, such as with extra biology. It goes `pip install \"pyjanitor[biology]\"`\r\n\r\nThe example of such implementations in `setup.py` is available at this link: https://setuptools.readthedocs.io/en/latest/setuptools.html#declaring-extras-optional-features-with-their-own-dependencies\n", "before_files": [{"content": "import re\nfrom pathlib import Path\n\nfrom setuptools import setup\n\n\ndef requirements():\n    with open(\"requirements.txt\", \"r+\") as f:\n        return f.read()\n\n\ndef generate_long_description() -> str:\n    \"\"\"\n    Extra chunks from README for PyPI description.\n\n    Target chunks must be contained within `.. pypi-doc` pair comments,\n    so there must be an even number of comments in README.\n\n    :returns: Extracted description from README\n\n    \"\"\"\n    # Read the contents of README file\n    this_directory = Path(__file__).parent\n    with open(this_directory / \"README.rst\", encoding=\"utf-8\") as f:\n        readme = f.read()\n\n    # Find pypi-doc comments in README\n    indices = [m.start() for m in re.finditer(\".. pypi-doc\", readme)]\n    if len(indices) % 2 != 0:\n        raise Exception(\"Odd number of `.. pypi-doc` comments in README\")\n\n    # Loop through pairs of comments and save text between pairs\n    long_description = \"\"\n    for i in range(0, len(indices), 2):\n        start_index = indices[i] + 11\n        end_index = indices[i + 1]\n        long_description += readme[start_index:end_index]\n    return long_description\n\n\nsetup(\n    name=\"pyjanitor\",\n    version=\"0.18.2\",\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    long_description=generate_long_description(),\n    long_description_content_type=\"text/x-rst\",\n)\n", "path": "setup.py"}]}