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+=====================================================
+Supporting both Python 2 and Python 3 with Setuptools
+=====================================================
+
+Starting with Distribute version 0.6.2 and Setuptools 0.7, the Setuptools
+project supported Python 3. Installing and
+using setuptools for Python 3 code works exactly the same as for Python 2
+code.
+
+Setuptools provides a facility to invoke 2to3 on the code as a part of the
+build process, by setting the keyword parameter ``use_2to3`` to True, but
+the Setuptools strongly recommends instead developing a unified codebase
+using `six <https://pypi.org/project/six/>`_,
+`future <https://pypi.org/project/future/>`_, or another compatibility
+library.
+
+
+Using 2to3
+==========
+
+Setuptools attempts to make the porting process easier by automatically
+running
+2to3 as a part of running tests. To do so, you need to configure the
+setup.py so that you can run the unit tests with ``python setup.py test``.
+
+See :ref:`test` for more information on this.
+
+Once you have the tests running under Python 2, you can add the use_2to3
+keyword parameters to setup(), and start running the tests under Python 3.
+The test command will now first run the build command during which the code
+will be converted with 2to3, and the tests will then be run from the build
+directory, as opposed from the source directory as is normally done.
+
+Setuptools will convert all Python files, and also all doctests in Python
+files. However, if you have doctests located in separate text files, these
+will not automatically be converted. By adding them to the
+``convert_2to3_doctests`` keyword parameter Setuptools will convert them as
+well.
+
+By default, the conversion uses all fixers in the ``lib2to3.fixers`` package.
+To use additional fixers, the parameter ``use_2to3_fixers`` can be set
+to a list of names of packages containing fixers. To exclude fixers, the
+parameter ``use_2to3_exclude_fixers`` can be set to fixer names to be
+skipped.
+
+An example setup.py might look something like this::
+
+    from setuptools import setup
+
+    setup(
+        name='your.module',
+        version='1.0',
+        description='This is your awesome module',
+        author='You',
+        author_email='your@email',
+        package_dir={'': 'src'},
+        packages=['your', 'you.module'],
+        test_suite='your.module.tests',
+        use_2to3=True,
+        convert_2to3_doctests=['src/your/module/README.txt'],
+        use_2to3_fixers=['your.fixers'],
+        use_2to3_exclude_fixers=['lib2to3.fixes.fix_import'],
+    )
+
+Differential conversion
+-----------------------
+
+Note that a file will only be copied and converted during the build process
+if the source file has been changed. If you add a file to the doctests
+that should be converted, it will not be converted the next time you run
+the tests, since it hasn't been modified. You need to remove it from the
+build directory. Also if you run the build, install or test commands before
+adding the use_2to3 parameter, you will have to remove the build directory
+before you run the test command, as the files otherwise will seem updated,
+and no conversion will happen.
+
+In general, if code doesn't seem to be converted, deleting the build directory
+and trying again is a good safeguard against the build directory getting
+"out of sync" with the source directory.
+
+Distributing Python 3 modules
+=============================
+
+You can distribute your modules with Python 3 support in different ways. A
+normal source distribution will work, but can be slow in installing, as the
+2to3 process will be run during the install. But you can also distribute
+the module in binary format, such as a binary egg. That egg will contain the
+already converted code, and hence no 2to3 conversion is needed during install.
+
+Advanced features
+=================
+
+If you don't want to run the 2to3 conversion on the doctests in Python files,
+you can turn that off by setting ``setuptools.use_2to3_on_doctests = False``.