from typing import List


def _split_list(string: str) -> List[str]:
    """Assumes an input of the form `[s1, s2, s3, ..., sn]`,
    where each si may itself contain lists."""
    assert string[0] == "[" and string[-1] == "]"
    nesting_depth = 0
    all_strings = []
    current_string = ""
    for character in string[1:-1]:
        if character == "," and nesting_depth == 0:
            all_strings.append(current_string)
            current_string = ""
            continue

        if character == "[":
            nesting_depth += 1
        elif character == "]":
            nesting_depth -= 1
        current_string += character
    if current_string != "":
        all_strings.append(current_string)
    return [string.strip() for string in all_strings]