diff --git a/src/amuse/community/mocassin/patch_files.py b/src/amuse/community/mocassin/patch_files.py
index 745536d73c..a913ee6fb1 100755
--- a/src/amuse/community/mocassin/patch_files.py
+++ b/src/amuse/community/mocassin/patch_files.py
@@ -6,53 +6,78 @@
 import re
 
 PATCHESDIR = "patches"
-QUILT_PC   = ".pc"
+QUILT_PC = ".pc"
 
-def execute_command_line(arguments, cwd = None):
-    process = subprocess.Popen(arguments, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd = cwd)
+
+def execute_command_line(arguments, cwd=None):
+    process = subprocess.Popen(
+        arguments, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=cwd
+    )
     stdoutstring, stderrstring = process.communicate()
     returncode = process.poll()
     return stdoutstring, stderrstring, returncode
-    
+
+
 def which(executablename):
-    stdoutstring, stderrstring, returncode = execute_command_line(['which', executablename])
+    stdoutstring, stderrstring, returncode = execute_command_line(
+        ["which", executablename]
+    )
     if not returncode == 0:
         return None
     else:
         return stdoutstring
-    
+
+
 def is_quilt_installed():
-    path = which('quilt')
+    path = which("quilt")
     if path is None:
         return False
-        
-    stdoutstring, stderrstring, returncode = execute_command_line(['quilt', '--version'])
+
+    stdoutstring, stderrstring, returncode = execute_command_line(
+        ["quilt", "--version"]
+    )
     if not returncode == 0:
         return False
-    
-    version_re = re.compile(r'(\d).(\d\d)')
-    match = version_re.match(stdoutstring)
+
+    version_re = re.compile(r"(\d).(\d\d)")
+    match = version_re.match(str(stdoutstring))
     if not match:
         return False
-    
+
     return True
 
+
 def apply_patches_using_quilt():
-    returncode = subprocess.call(['quilt', 'push', '-a'])
+    returncode = subprocess.call(["quilt", "push", "-a"])
     if not returncode == 0:
-        raise Exception("error in applying the patches, please apply by hand using quilt push")
-        
+        raise Exception(
+            "error in applying the patches, please apply by hand using quilt push"
+        )
+
+
 def undo_patches_using_quilt():
-    returncode = subprocess.call(['quilt', 'pop', '-a'])
+    returncode = subprocess.call(["quilt", "pop", "-a"])
     if not returncode == 0:
-        raise Exception("error in undoing the patches, please undo by hand using quilt pop -a")
+        raise Exception(
+            "error in undoing the patches, please undo by hand using quilt pop -a"
+        )
+
 
 def run_patch(patchname, patchfile):
-    arguments = ['patch', '-p1', '--backup', '--prefix={0}/{1}/'.format(QUILT_PC, patchname), '-E', '-i', patchfile]
+    arguments = [
+        "patch",
+        "-p1",
+        "--backup",
+        "--prefix={0}/{1}/".format(QUILT_PC, patchname),
+        "-E",
+        "-i",
+        patchfile,
+    ]
     returncode = subprocess.call(arguments)
     if not returncode == 0:
         raise Exception("could not apply patch {0}".format(patchname))
-        
+
+
 def apply_patches_using_patch():
     with open("patches/series", "r") as f:
         lines = f.readlines()
@@ -61,12 +86,13 @@ def apply_patches_using_patch():
     for patch in patches:
         path = os.path.join(PATCHESDIR, patch)
         run_patch(patch, path)
-        
-def main(undo_patches = False):
-    print("checking if quilt is installed ... ", end=' ') 
+
+
+def main(undo_patches=False):
+    print("checking if quilt is installed ... ", end=" ")
     if not is_quilt_installed():
         print("no")
-        
+
         if undo_patches:
             print("quilt is not installed, cannot undo the patches")
             sys.exit(1)
@@ -75,7 +101,7 @@ def main(undo_patches = False):
             apply_patches_using_patch()
     else:
         print("yes")
-        
+
         if undo_patches:
             print("quilt is install, will try to undo the patches")
             undo_patches_using_quilt()
@@ -83,6 +109,7 @@ def main(undo_patches = False):
             print("applying patches to source code")
             apply_patches_using_quilt()
             print("all patches applied")
-    
-if __name__ == '__main__':
+
+
+if __name__ == "__main__":
     main()