/**
 * Removes unindented lines from a code block based on specified rules.
 *
 * This function processes a multi-line string of code and removes lines that are not indented, 
 * except for those protected by specific conditions. The function starts removing lines only 
 * after encountering a line that starts with the `protect_before` string. Additionally, lines 
 * that start with any string in the `exceptions` list are preserved. If a line starts with any 
 * string in the `trim_tails` list, all subsequent lines are removed.
 *
 * Args:
 *     code (str): The multi-line string of code to process.
 *     protect_before (str): The string that, when found at the start of a line, enables the 
 *         protection of subsequent lines from being removed.
 *     exceptions (list[str]): A list of strings. Lines starting with any of these strings 
 *         are preserved even if they are unindented.
 *     trim_tails (list[str]): A list of strings. If a line starts with any of these strings, 
 *         all subsequent lines are removed.
 *
 * Returns:
 *     str: The processed code with unindented lines removed according to the specified rules.
 */
You should write code starting with:
from typing import List

def remove_unindented_lines(
    code: str, protect_before: str, execeptions: List[str], trim_tails: List[str]
) -> str:
    # TODO: Implement this function based on the docstring.
    pass

