docs: def d8flowdir(np, filleddem, flowdir, slope, workingdir=None, mpiexedir=None, exedir=None,
                    log_file=None, runtime_file=None, hostfile=None):
          """Run D8 flow direction"""
          fname = TauDEM.func_name('d8flowdir')
          return TauDEM.run(FileClass.get_executable_fullpath(fname, exedir),
                            {'-fel': filleddem}, workingdir,
                            None,
                            {'-p': flowdir, '-sd8': slope},
                            {'mpipath': mpiexedir, 'hostfile': hostfile, 'n': np},
                            {'logfile': log_file, 'runtimefile': runtime_file})