import subprocess
#   Pfad zur "DHI.Mike1D.Application.exe"
mike1d = 'c:\\"Program Files (x86)"\\DHI\\2017\\bin\\x64\\DHI.Mike1D.Application.exe'
#
#   erster Aufruf
returned_value = subprocess.call(mike1d + ' s04Basis.m1dx', shell=True)
print returned_value
#
#   zweiter Aufruf
returned_value = subprocess.call(mike1d + ' s05Basis.m1dx', shell=True)
print returned_value