extracting data from typing types

Checking if a variable conforms to a typing object

To check if string_list conforms to string_list_class, you can use the typeguard type checking library.

from typeguard import check_type

try:
    check_type('string_list', string_list, string_list_class)
    print("string_list conforms to string_list_class")
except TypeError:
    print("string_list does not conform to string_list_class")

Checking the generic type of a typing object

To check if string_list_class is a list type, you can use the typing_inspect library:

from typing_inspect import get_origin
from typing import List

get_origin(List[str]) # -> List

You could also use the private __origin__ field, but there is no stability guarantee for it.

List[str].__origin__ # -> list

Checking the type argument of a typing object

To check the class, that string_list_class is a list of, you can use the typing_inspect library again.

from typing_inspect import get_parameters
from typing import List

assert get_parameters(List[str])[0] == str

As before, there is also a private field you can use if you like to take risks

List[str].__args__[0] # -> str