Suppose we have a list `variables` with the variables `[a, b, c]`. The code shall check if the variable value is a of type string with the text `"None"`. The variable value shall be updated to `""` if true. Using a for loop, I would write:

```
a = 1
b = 2
c = 3
variables = [a, b, c]

for i in range(len(variables)):
    variables[i] = 55

print(variables)
print(a, b, c)

```

This outputs:

```
[55, 55, 55]
1 2 3

```

Why don't the variables update their value?