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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def try_run_inschek(pst):
 """ attempt to run INSCHEK for each instruction file, model output file pair in a pyemu.Pst. If the run is successful, the INSCHEK written .obf file is used to populate the pst.observation_data.obsval attribute Parameters pst : (pyemu.Pst) """

    for ins_file,out_file in zip(pst.instruction_files,pst.output_files):
        df = _try_run_inschek(ins_file,out_file)
        if df is not None:
            pst.observation_data.loc[df.index, "obsval"] = df.obsval