08-12-2015
In Python the assignment operator `=' never copies data. Whatever is at the left of the `=' is a binding label to a value, not a variable per se. This is significant, since moving labels do not produce another variable.
I recommend you watch
Ned Batchelder -
Facts and Myths about Python names and values - PyCon 2015 if you are interested on it.
At 15:50 you'll get presentation related to your query, but I would watch it from the beginning since the concept of binding and rebinding labels builds from understanding mutable and immutable values.
Hope it helps.
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LEARN ABOUT DEBIAN
dh_pycentral
DH_PYCENTRAL(1) Debhelper DH_PYCENTRAL(1)
NAME
dh_pycentral - use the python-central framework to handle Python modules and extensions
SYNOPSIS
dh_pycentral [debhelper options] [-n] [-Xitem] [-V version] [module dirs ...]
DESCRIPTION
dh_pycentral is a debhelper program that will scan your package, detect public Python modules and move them in /usr/share/pycentral so that
python-central can byte-compile those for all supported Python versions. Extensions are kept into the original installation location.
Moving the files to the pycentral location and adding symbolic links to /usr/lib/pythonX.Y/*-packages can be done by setting the
environment varibale DH_PYCENTRAL to a string containing the string include-links.
Moving the files to the pycentral location can be disabled by setting the environment varibale DH_PYCENTRAL to a string containing the
string nomove.
The functionality to shorten the time of unavailabilty of files during unpack and configure has been removed (symlinking files in the
preinst and not removing the symlinked files on upgrade) in version 0.6.9.
You must have filled the XS-Python-Version header to indicate the set of python versions that are going to be supported. dh_pycentral
expects the XB-Python-Version for each binary package it is supposed to work on.
dh_pycentral will also generate substitution variables: the ${python:Provides} variable will contain versioned provides of the package (if
the package's name starts with "python-"). A python-foo package could provide "python2.3-foo" and "python2.4-foo" at the same time. Python
extensions have to provide those whereas it's only option for pure python modules.
The ${python:Versions} variable should be used to provide the required XB-Python-Version field listing the python versions supported by the
package.
OPTIONS
module dirs
If your package installs python modules in non-standard directories, you can make dh_pycentral check those directories by passing their
names on the command line. By default, it will check /usr/lib/$PACKAGE, /usr/share/$PACKAGE, /usr/lib/games/$PACKAGE,
/usr/share/games/$PACKAGE, /usr/lib/python?.?/site-packages and /usr/lib/python?.?/dist-packages.
Note: only /usr/lib/python?.?/site-packages and the extra names on the command line are searched for binary (.so) modules.
-V version
If the .py files your package ships are meant to be used by a specific pythonX.Y version, you can use this option to specify the
desired version, such as 2.3. Do not use if you ship modules in /usr/lib/site-python.
With the new policy, this option is mostly deprecated. Use the XS-Python-Field to indicate that you're using a specific python version.
-n, --noscripts
Do not modify postinst/postrm scripts.
-Xitem, --exclude=item
Exclude files that contain "item" anywhere in their filename from being taken into account to generate the python dependency. You may
use this option multiple times to build up a list of things to exclude.
CONFORMS TO
Python policy, version 0.4.1 (2006-06-20)
SEE ALSO
debhelper(7)
This program is a part of python-central but is made to work with debhelper.
AUTHORS
Raphael Hertzog <hertzog@debian.org>
Also includes bits of the old dh_python written by Josselin Mouette <joss@debian.org> who used many ideas from Brendan O'Dea
<bod@debian.org>.
2011-04-14 DH_PYCENTRAL(1)