prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Python 3.9 compatibility
  Python 3.9 [is out](https://docs.python.org/3.9/whatsnew/3.9.html). We should ensure that we are compatible, so there are a couple of things to do
  
  * [x] Create a fresh Python 3.9 environment.yml (with current package versions)
  * [x] Update Travis and Appveyor CI setup files
    - [x] Check if the Appveyor 3.8 build can use the 3.8 miniconda, not 3.7, now
    - [x] I think we should relax the python version specifiers in the environment.yml to major.minor (i.e. python 3.8, not 3.8.1), to also get python bugfixes, even though it's a bit less strict in CI version stability.
    - [x] Check if we should bump Trais ubuntu version to the current LTS focal (20.04)
  * The conda-forge package is repackaged automatically, apparently - it's already available.
  
  </issue>
  <code>
  [start of setup.py]
  1 #
  2 # This file is part of the PyMeasure package.
  3 #
  4 # Copyright (c) 2013-2020 PyMeasure Developers
  5 #
  6 # Permission is hereby granted, free of charge, to any person obtaining a copy
  7 # of this software and associated documentation files (the "Software"), to deal
  8 # in the Software without restriction, including without limitation the rights
  9 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10 # copies of the Software, and to permit persons to whom the Software is
  11 # furnished to do so, subject to the following conditions:
  12 #
  13 # The above copyright notice and this permission notice shall be included in
  14 # all copies or substantial portions of the Software.
  15 #
  16 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22 # THE SOFTWARE.
  23 #
  24 
  25 
  26 from setuptools import setup, find_packages
  27 
  28 setup(
  29     name='PyMeasure',
  30     version='0.8.0',
  31     author='PyMeasure Developers',
  32     packages=find_packages(),
  33     scripts=[],
  34     url='https://github.com/ralph-group/pymeasure',
  35     download_url='https://github.com/ralph-group/pymeasure/tarball/v0.8.0',
  36     license='MIT License',
  37     description='Scientific measurement library for instruments, experiments, and live-plotting',
  38     long_description=open('README.rst').read() + "\n\n" + open('CHANGES.txt').read(),
  39     install_requires=[
  40         "numpy >= 1.6.1",
  41         "pandas >= 0.14",
  42         "pyvisa >= 1.8",
  43         "pyserial >= 2.7",
  44         "pyqtgraph >= 0.9.10"
  45     ],
  46     extras_require={
  47         'matplotlib': ['matplotlib >= 2.0.2'],
  48         'tcp': [
  49             'zmq >= 16.0.2',
  50             'cloudpickle >= 0.3.1'
  51         ],
  52         'python-vxi11': ['python-vxi11 >= 0.9']
  53     },
  54     setup_requires=[
  55         'pytest-runner'
  56     ],
  57     tests_require=[
  58         'pytest >= 2.9.1',
  59         'pytest-qt >= 2.4.0'
  60     ],
  61     classifiers=[
  62         "Development Status :: 4 - Beta",
  63         "Intended Audience :: Science/Research",
  64         "License :: OSI Approved :: MIT License",
  65         "Operating System :: MacOS",
  66         "Operating System :: Microsoft :: Windows",
  67         "Operating System :: POSIX",
  68         "Operating System :: Unix",
  69         "Programming Language :: Python :: 3 :: Only",
  70         "Programming Language :: Python :: 3.6",
  71         "Programming Language :: Python :: 3.7",
  72         "Programming Language :: Python :: 3.8",
  73         "Topic :: Scientific/Engineering",
  74     ],
  75     keywords="measure instrument experiment control automate graph plot"
  76 )
  77
  [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
  @@ -70,6 +70,7 @@
           "Programming Language :: Python :: 3.6",
           "Programming Language :: Python :: 3.7",
           "Programming Language :: Python :: 3.8",
  +        "Programming Language :: Python :: 3.9",
           "Topic :: Scientific/Engineering",
       ],
       keywords="measure instrument experiment control automate graph plot"
  
verification_info: {"golden_diff": "diff --git a/setup.py b/setup.py\n--- a/setup.py\n+++ b/setup.py\n@@ -70,6 +70,7 @@\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         \"Topic :: Scientific/Engineering\",\n     ],\n     keywords=\"measure instrument experiment control automate graph plot\"\n", "issue": "Python 3.9 compatibility\nPython 3.9 [is out](https://docs.python.org/3.9/whatsnew/3.9.html). We should ensure that we are compatible, so there are a couple of things to do\r\n\r\n* [x] Create a fresh Python 3.9 environment.yml (with current package versions)\r\n* [x] Update Travis and Appveyor CI setup files\r\n  - [x] Check if the Appveyor 3.8 build can use the 3.8 miniconda, not 3.7, now\r\n  - [x] I think we should relax the python version specifiers in the environment.yml to major.minor (i.e. python 3.8, not 3.8.1), to also get python bugfixes, even though it's a bit less strict in CI version stability.\r\n  - [x] Check if we should bump Trais ubuntu version to the current LTS focal (20.04)\r\n* The conda-forge package is repackaged automatically, apparently - it's already available.\n", "before_files": [{"content": "#\n# This file is part of the PyMeasure package.\n#\n# Copyright (c) 2013-2020 PyMeasure Developers\n#\n# Permission is hereby granted, free of charge, to any person obtaining a copy\n# of this software and associated documentation files (the \"Software\"), to deal\n# in the Software without restriction, including without limitation the rights\n# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell\n# copies of the Software, and to permit persons to whom the Software is\n# furnished to do so, subject to the following conditions:\n#\n# The above copyright notice and this permission notice shall be included in\n# all copies or substantial portions of the Software.\n#\n# THE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\n# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,\n# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE\n# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER\n# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,\n# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN\n# THE SOFTWARE.\n#\n\n\nfrom setuptools import setup, find_packages\n\nsetup(\n    name='PyMeasure',\n    version='0.8.0',\n    author='PyMeasure Developers',\n    packages=find_packages(),\n    scripts=[],\n    url='https://github.com/ralph-group/pymeasure',\n    download_url='https://github.com/ralph-group/pymeasure/tarball/v0.8.0',\n    license='MIT License',\n    description='Scientific measurement library for instruments, experiments, and live-plotting',\n    long_description=open('README.rst').read() + \"\\n\\n\" + open('CHANGES.txt').read(),\n    install_requires=[\n        \"numpy >= 1.6.1\",\n        \"pandas >= 0.14\",\n        \"pyvisa >= 1.8\",\n        \"pyserial >= 2.7\",\n        \"pyqtgraph >= 0.9.10\"\n    ],\n    extras_require={\n        'matplotlib': ['matplotlib >= 2.0.2'],\n        'tcp': [\n            'zmq >= 16.0.2',\n            'cloudpickle >= 0.3.1'\n        ],\n        'python-vxi11': ['python-vxi11 >= 0.9']\n    },\n    setup_requires=[\n        'pytest-runner'\n    ],\n    tests_require=[\n        'pytest >= 2.9.1',\n        'pytest-qt >= 2.4.0'\n    ],\n    classifiers=[\n        \"Development Status :: 4 - Beta\",\n        \"Intended Audience :: Science/Research\",\n        \"License :: OSI Approved :: MIT License\",\n        \"Operating System :: MacOS\",\n        \"Operating System :: Microsoft :: Windows\",\n        \"Operating System :: POSIX\",\n        \"Operating System :: Unix\",\n        \"Programming Language :: Python :: 3 :: Only\",\n        \"Programming Language :: Python :: 3.6\",\n        \"Programming Language :: Python :: 3.7\",\n        \"Programming Language :: Python :: 3.8\",\n        \"Topic :: Scientific/Engineering\",\n    ],\n    keywords=\"measure instrument experiment control automate graph plot\"\n)\n", "path": "setup.py"}]}