[ZDP] BackTalk to Document Zope Developer's Guide (2.4 edition)/Zope Products

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A comment to the paragraph below was recently added via http://www.zope.org/Documentation/Books/ZDG/current/Products.stx#3-99

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      Another solution is to use the standard Python pickling hook
      '__setstate__', however, this is in general more error prone and
      complex.

        % Anonymous User - Nov. 8, 2002 9:26 pm:
         I'd like to get examples here.

         Instead of pickling, how about including methods for export to/import from disk.
         these may be editable strings (__repr__) for export and python eval for import. 
         caveat: eval doesnt like newlines.
         The next more complicated solution is parse/unparse methods for im/export.
         This of course must be included in the very first distributed product and then
         migrating to a newer version still requires manual work for each instance
         (export, delete old instance, create new instance, import).
         Or is there a way to modify product instances in the ZODB? example, plz.