docs: def threshold(np, acc, stream_raster, threshold=100., workingdir=None,
                    mpiexedir=None, exedir=None, log_file=None, runtime_file=None, hostfile=None):
          """Run threshold for stream raster"""
          fname = TauDEM.func_name('threshold')
          return TauDEM.run(FileClass.get_executable_fullpath(fname, exedir),
                            {'-ssa': acc}, workingdir,
                            {'-thresh': threshold},
                            {'-src': stream_raster},
                            {'mpipath': mpiexedir, 'hostfile': hostfile, 'n': np},
                            {'logfile': log_file, 'runtimefile': runtime_file})