pseudo-dep-serpent-msbr

def main():
    step = 0 
    output[step] = somefile
    for step in dep_steps:
        infile = rewrite_infile(output[step-1])
        output[step] = run_serpent(infile)

def rewrite_infile(outfile):
#do stuff with pyne


def run_serpent(infile):
    # copy infile to runfile
    subprocess.check_output(['qsub', 'serp_qsub_file'])
    # copy outfile to output[step]
    return output[step]