Extract the keys in `names` from the `kwargs`.

def extract_kwargs(names:Collection[str], kwargs:KWArgs):
    "Extract the keys in `names` from the `kwargs`."
    new_kwargs = {}
    for arg_name in names:
        if arg_name in kwargs:
            arg_val = kwargs.pop(arg_name)
            new_kwargs[arg_name] = arg_val
    return new_kwargs, kwargs