gistfile1.py

class Person(object):

    def __init__(self, name, *attrs):
        self.name = name
        self.attrs = set()
        self.can(*attrs)

    def does(self, what):
        if what in self.attrs: return True
        return False

    def can(self, *what):
        self.attrs |= set(what)

people = set([
    Person("Max", "surf", "swim"),
    Person("Charlie", "dig", "fly")
])

surfers = filter(lambda x: x.does("surf"), people)
assert surfers.pop().name == "Max"