You are given a code:

def main_solution(x):
    return (('gvtknz' + 'jblz') + func_4('ylgz'))

Can you predict the output of `main_solution("tywtl")` 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": "tywtl"}, "ref_output": "gvtknzjblzylgz", "ref_code": "def main_solution(x):\n    return (('gvtknz' + 'jblz') + func_4('ylgz'))", "funcname": "main_solution"}
rule