How to adress a attribute created by setattr()?

I want to create a Micropython-Class for an LED-Strip. When initializing, the class can be called with any number of color=Pin pairs.
So my idea was to call def __init__(self, **kwargs) and then use:

for color, pin in kwargs.items():
    setattr(self, color, PWM(Pin(pin)))

I want to refer later (e.g. to change the PWM-value with self.color.duty(). My problem is, I don’t know, how to create any kind of list of all created attributes, so I can iterate through them later on.
Thinking about something like:

for color in color_list:
    color.duty(number_gained_via_mqtt)

But how can I put the created attributes into this "color_list"?

Update

Thank you for the first Answers! The Problem is, a simple list of the keys does not solve my problem. I can’t call self.key_from_list (as far as I know).

E.g. if I create a liste from keys color_list=["r","g","b","w"]I can’t (or don’t know how to) iterate through them.

for color in color_list:
    self.color.duty(0)

will not work, because the list only contains strings and I don’t know, how to call attributes of my class with that name (if that makes any sense)

The full code looks like this:

class Stripe():
    def __init__(self, **kwargs):
        self.on = 1
        self.leds = dict()
        for key, value in kwargs.items():
            setattr(self, key, PWM(Pin(value)))
            self.leds[key] = 255
    
    def display(self):
        if self.on:
            for key in self.leds:
                self.key.duty(self.leds.get(key)) # does not work
        else:
            for key in self.leds:
                 self.key.duty(0) # does not work either

Update 2 – Solved

Thank you guys for the answers. Using a dictionary instead of attributes solves the problem.

>Solution :

Since your colors are the keys of kwargs, which is a regular dictionary, you can do

self.color_list = list(kwargs.keys())

Then you can address them as

for color in self.color_list:
    getattr(self, color).duty(number_gained_via_mqtt)

If you just want a list of the PWM objects, you can do that too:

self.color_list = []
for color, pin in kwargs.items():
    pwm = PWM(Pin(pin))
    setattr(self, color, pwm)
    self.color_list.append(pwm)

Then you can do

for color in self.color_list:
    color.duty(number_gained_via_mqtt)

A better option might be to store everything into a dictionary rather than the instance __dict__, where all the attributes are mixed together:

self.colors = {color: PWM(Pin(pin)) for color, pin kwargs.items()}

Then you can access it much simpler:

for pin in self.colors.values():
    pin.duty(number_gained_via_mqtt)