Question about isinstance()

[Mr.Rech]

After reading all your comments and thinking a little to my specific
case, I think it is definetively better to go with the "isinstance()"
implementation. My objects represent mathematical function defined over
a numerical grid, and I hardly think of an unrelated class objects that
could be compared with them in a meaningfull way.

Thanks again to all of you for helping me to better understand another
piece of the Python's world. ;-)

 Andrea