Generic logic/conditional class or library for classification of data

[Basilisk96]

This topic is difficult to describe in one subject sentence...

Has anyone come across the application of the simple statement "if
(object1's attributes meet some conditions) then (set object2's
attributes to certain outcomes)", where "object1" and "object2" are
generic objects, and the "conditions" and "outcomes" are dynamic run-
time inputs? Typically, logic code for any application out there is
hard-coded. I have been working with Python for a year, and its
flexibility is nothing short of amazing. Wouldn't it be possible to
have a class or library that can do this sort of dynamic logic?

The main application of such code would be for classification
algorithms which, based on the attributes of a given object, can
classify the object into a scheme. In general, conditions for
classification can be complex, sometimes involving a collection of
"and", "or", "not" clauses. The simplest outcome would involve simply
setting a few attributes of the output object to given values if the
input condition is met. So each such "if-then" clause can be viewed as
a rule that is custom-defined at runtime.

As a very basic example, consider a set of uncategorized objects that
have text descriptions associated with them. The objects are some type
of tangible product, e.g., books. So the input object has a
Description attribute, and the output object (a categorized book)
would have some attributes like Discipline, Target audience, etc.
Let's say that one such rule is "if ( 'description' contains
'algebra') then ('discipline' = 'math', 'target' = 'student') ". Keep
in mind that all these attribute names and their values are not known
at design time.

Is there one obvious way to do this in Python?
Perhaps this is more along the lines of data mining methods?
Is there a library with this sort of functionality out there already?

Any help will be appreciated.