"""Parses a string of comma-separated API keys into a list of stripped keys.

Args:
    api_keys (str): A string containing comma-separated API keys. If empty, returns an empty list.

Returns:
    List[str]: A list of API keys with leading and trailing whitespace removed. If the input string is empty, returns an empty list.
"""
You should write code starting with:
from typing import List

def _parse_api_keys(api_keys: str) -> List[str]:
    # TODO: Implement this function
    pass

