You are given a code:

def main_solution(x):
    return func_13(('hxkg' + 'akpkg'), '_')

Can you predict the output of `main_solution("xiwqdvitw")` 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": "xiwqdvitw"}, "ref_output": "h_x_k_g_a_k_p_k_g", "ref_code": "def main_solution(x):\n    return func_13(('hxkg' + 'akpkg'), '_')", "funcname": "main_solution"}
rule