How to get instance variables in Python?

Is there a built-in method in Python to get an array of all a class' instance variables? For example, if I have this code:

class hi:
  def __init__(self):
    self.ii = "foo"
    self.kk = "bar"

Is there a way for me to do this:

>>> mystery_method(hi)
["ii", "kk"]

Edit: I originally had asked for class variables erroneously.

Every object has a __dict__ variable containing all the variables and its values in it.

Try this

>>> hi_obj = hi()
>>> hi_obj.__dict__.keys()

Use vars()

class Foo(object):
    def __init__(self):
        self.a = 1
        self.b = 2

vars(Foo()) #==> {'a': 1, 'b': 2}
vars(Foo()).keys() #==> ['a', 'b']