You are given a code:

def main_solution(x):
    return func_20(func_15(x), func_13('lfeqvv', '|'))

Can you predict the output of `main_solution("bkz")` without writing any code? Please reason and put your final answer in the following json format: {"output": <your output>}, where <your output> should be the final string.
user
{"ref_input": {"x": "bkz"}, "ref_output": "\u00ablb|\u00bbf\u00ab|ke\u00bb|\u00abqz|\u00bbv|v", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_13('lfeqvv', '|'))", "funcname": "main_solution"}
rule