How to keep Dict[str, List] default method parameter as local to the method?

[zljubisic at gmail.com]

Hi,

consider this example:

from typing import Dict, List


class chk_params:
    def execute(self, params: Dict[str, List] = None):
        if params is None:
            params = {}

        for k, v in params.items():
            params[k] = [val + 10 for val in v]

        return params.values()

params = {
    'A' : [1],
    'B': [2],
    'C': [3],
    'D': [4],
    'E': [5]
}
print(params)
params_obj = chk_params()

print(params_obj.execute(params = params))
print(params)

Output is:
{'A': [1], 'B': [2], 'C': [3], 'D': [4], 'E': [5]}
dict_values([[11], [12], [13], [14], [15]])
{'A': [11], 'B': [12], 'C': [13], 'D': [14], 'E': [15]}

I expected that last print statement will show original parameters A=1, B=2... but this is not the case.

How to construct the method parameters, with params parameter as type of Dict[str, List], but at the same time keep params as local dictionary to the chk_params.execute() method?