You are given a code:

def main_solution(x):
    return (func_13(x, '_') + ('izslxr' + 'omwssd'))

Can you predict the output of `main_solution("zbystj")` 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": "zbystj"}, "ref_output": "z_b_y_s_t_jizslxromwssd", "ref_code": "def main_solution(x):\n    return (func_13(x, '_') + ('izslxr' + 'omwssd'))", "funcname": "main_solution"}
rule