python – Is there a python way to apply a function to several existing variables?

I have restructured one of my projects so that it is more elegant and readable. I arrived at a point where I want to apply a multivariate function, thus transforming the value of the variable. To my dismay, I realized that the loop for that I was using did not change the value of the variables.

For example:

                def change_value (x):
x = x * 2
back x
a = 5
b = 10
c = 15

for x in (a, b, c):
x = change_value (x)

print (a) #a does not really change.

The reason I want to do this is because I have created several datasets and a method that is reshaping them. Rather than explicitly passing each variable through the function on its own line, I would like to find a way to iterate.