foo.py

class Foo(object):
    _d = {}
    def __init__(self, *names):
        for name in names:
            self.add_property(name, name)

    def add_property(self, name, value):
        self._d[name] = value

    def getter(self, value):
        return "[[ {0} ]]".format(value)

    def setter(self, value):
        return value

    def __getattr__(self, name):
        if name not in self._d:
            raise AttributeError
        return self.getter(self._d[name])

    def __setattr__(self, name, value):
        if name in self._d:
            self._d[name] = self.setter(value)
        else:
            object.__setattr__(self, name, value)

foo = Foo("foo", "bar", "baz")

print foo.foo
print foo.bar
print foo.baz