pyisbn ISBN - A module for working with 10- and 13-digit ISBNs This module supports the calculation of ISBN checksums with ``calculate_checksum()``, the conversion between ISBN-10 and ISBN-13 with ``convert()`` and the validation of ISBNs with ``validate()``. All the ISBNs must be passed in as ``str`` types, even if it would seem reasonable to accept some ``int`` forms. The reason behind this is English speaking countries use ``0`` for their group identifier, and Python would treat ISBNs beginning with ``0`` as octal representations producing incorrect results. While it may be feasible to allow some cases as non-``str`` types the complexity in design and usage isn't worth the minimal benefit. The functions in this module also support 9-digit SBNs for people with older books in their collection. http://www.jnrowe.ukfsn.org/_downloads/pyisbn-0.5.0.tar.bz2 James Rowe d97bcb1a502a618a8a98290ea01fd0049bffdb29 0.5.0