see: http://www.careercup.com/page?pid=oracle-interview-questions&n=2

dynamic filter.py

#!/usr/bin/env python
# Jorge Niedbalski <jnr@pyrosome.org>

class Query:
    (c,d) = ([],[])

    def __init__(self):
        pass

    def a(self, d):
        self.d.append(d)
        return self

    def f(self, k, v):
        self.c.append((k, v))
        return self

    def g(self):
        for entry in self.d:
            cc = []
            for k,v in self.c:
                try:
                    cc.append(entry[k] == v)
                except KeyError:
                    pass		
                if any(cc):
                    yield entry

def f():
    persons = Query() \
        .a({'name': 'tester', 'address': 'test avenue 99'})\
        .a({'name': 'tester1', 'address': 'test avenue 100'})\
        .a({'name': 'tester2', 'address': 'test avenue 101'})\
        .f('name', 'tester').g()

    for person in persons:
        print person

f()