executing list of methods (and collecting results)

[Gerardo Herzig]

Hi all. Im in this situation: I want to perform several kind of 
(validating) methods to a given value.
Lets say i have a class named Number, and the following methods:
is_really_a_number(),
is_even(),
is_greater_than_zero(),
and so on. All of them returning booleans.

I want the collect_validators() method is to execute any of the above 
methods, and collect their names as items of a list (wich will be the 
collect_validators() return value).

My first approach is:

[code]
def collect_validators(self):
    v_dict = { 'is_really_a_number': is_really_a_number,
                      'is_even': is_even,
                      'is_greater_than_zero', is_greater_than_zero
                   }

       for name, meth in v_dict.items():
          result = meth()
          if result: yield name
[/code]

I wondering if is this a good pattern to apply, i like the way it looks 
like, at least to me it looks `natural', but...im calling every method 
twice here? One in v_dict and again on the dict iteration?

Any suggestion will be great!

Thanks!
Gerardo