Note: The type hints included in this package come from the typeshed project, and are hence distributed under the Apache License 2.0 rather than under the Python Software License that covers the module implementation and test suite. A. HISTORY OF THE SOFTWARE ========================== contextlib2 is a derivative of the contextlib module distributed by the PSF as part of the Python standard library. According, it is itself redistributed under the PSF license (reproduced in full below). As the contextlib module was added only in Python 2.5, the licenses for earlier Python versions are not applicable and have not been included. Python was created in the early 1990s by Guido van Rossum at Stichting Mathematisch Centrum (CWI, see http://www.cwi.nl) in the Netherlands as a successor of a language called ABC. Guido remains Python's principal author, although it includes many contributions from others. In 1995, Guido continued his work on Python at the Corporation for National Research Initiatives (CNRI, see http://www.cnri.reston.va.us) in Reston, Virginia where he released several versions of the software. In May 2000, Guido and the Python core development team moved to BeOpen.com to form the BeOpen PythonLabs team. In October of the same year, the PythonLabs team moved to Digital Creations (now Zope Corporation, see http://www.zope.com). In 2001, the Python Software Foundation (PSF, see http://www.python.org/psf/) was formed, a non-profit organization created specifically to own Python-related Intellectual Property. Zope Corporation is a sponsoring member of the PSF. All Python releases are Open Source (see http://www.opensource.org for the Open Source Definition). Historically, most, but not all, Python releases have also been GPL-compatible; the table below summarizes the various releases that included the contextlib module. Release Derived Year Owner GPL- from compatible? (1) 2.5 2.4 2006 PSF yes 2.5.1 2.5 2007 PSF yes 2.5.2 2.5.1 2008 PSF yes 2.5.3 2.5.2 2008 PSF yes 2.6 2.5 2008 PSF yes 2.6.1 2.6 2008 PSF yes 2.6.2 2.6.1 2009 PSF yes 2.6.3 2.6.2 2009 PSF yes 2.6.4 2.6.3 2009 PSF yes 2.6.5 2.6.4 2010 PSF yes 3.0 2.6 2008 PSF yes 3.0.1 3.0 2009 PSF yes 3.1 3.0.1 2009 PSF yes 3.1.1 3.1 2009 PSF yes 3.1.2 3.1.1 2010 PSF yes 3.1.3 3.1.2 2010 PSF yes 3.1.4 3.1.3 2011 PSF yes 3.2 3.1 2011 PSF yes 3.2.1 3.2 2011 PSF yes 3.2.2 3.2.1 2011 PSF yes 3.3 3.2 2012 PSF yes Footnotes: (1) GPL-compatible doesn't mean that we're distributing Python under the GPL. All Python licenses, unlike the GPL, let you distribute a modified version without making your changes open source. The GPL-compatible licenses make it possible to combine Python with other software that is released under the GPL; the others don't. Thanks to the many outside volunteers who have worked under Guido's direction to make these releases possible. B. 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