[Zope] revised ZClass question

[Sam Gendler]

I have a product built with a ZClass.  In the Product (called
MethodClass), I have an external method that contains an instance of an
HTMLParser from htmllib.  That external method is called from the
MethodClass_add function (the constructor).  I also want to call this
external method from a method within the ZClass.  When I call it with
dtml-call, I get a NameError, which implies that the external method is
not acquired,  I have no idea how acquisition works within a ZClass
product, however.  Then I tried creating an external method inside the
ZClass that calls the same function, and I get an ugly error that does
not happen when the method is called from the Product constructor:

Error Type: TypeError
Error Value: __add__ nor __radd__ defined for these operands

Traceback (innermost last):
  File /home/sgendler/Zope-2.0.1-src/lib/python/ZPublisher/Publish.py,
line 214, in publish_module
  File /home/sgendler/Zope-2.0.1-src/lib/python/ZPublisher/Publish.py,
line 179, in publish
  File /home/sgendler/Zope-2.0.1-src/lib/python/Zope/__init__.py, line
201, in zpublisher_exception_hook
    (Object: <string>)
  File /home/sgendler/Zope-2.0.1-src/lib/python/ZPublisher/Publish.py,
line 165, in publish
  File /home/sgendler/Zope-2.0.1-src/lib/python/ZPublisher/mapply.py,
line 160, in mapply
    (Object: manage_stripUpload)
  File /home/sgendler/Zope-2.0.1-src/lib/python/ZPublisher/Publish.py,
line 102, in call_object
    (Object: manage_stripUpload)
  File /home/sgendler/Zope-2.0.1-src/lib/python/OFS/DTMLMethod.py, line
145, in __call__
    (Object: manage_stripUpload)
  File
/home/sgendler/Zope-2.0.1-src/lib/python/DocumentTemplate/DT_String.py,
line 502, in __call__
    (Object: manage_stripUpload)
  File
/home/sgendler/Zope-2.0.1-src/lib/python/DocumentTemplate/DT_Util.py,
line 321, in eval
    (Object: strip_extra_html(REQUEST['file'], REQUEST))
  File <string>, line 0, in ?
  File
/home/sgendler/Zope-2.0.1-src/lib/python/Products/ExternalMethod/ExternalMethod.py,
line 246, in __call__
    (Object: strip_extra_html)
    (Info: ((<ZPublisher.HTTPRequest.FileUpload instance at
85e6668>,<loads of stuff from the REQUEST structure was here, snipped>,
{}, None))
  File /home/sgendler/Zope-2.0.1-src/Extensions/test.py, line 19, in
StripFile
  File /var/tmp/python-root/usr/lib/python1.5/sgmllib.py, line 82, in
feed
TypeError: (see above)