You are given a code:

def main_solution(x):
    return func_4('nvhrds')

Can you predict the output of `main_solution("mboaz")` 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": "mboaz"}, "ref_output": "nvhrds", "ref_code": "def main_solution(x):\n    return func_4('nvhrds')", "funcname": "main_solution"}
rule