future proofing is good, but...

since print() was made a function in py3, i can predict at some point
that return will be made a func as well. sure, good.
but "return()" *currently* returns an empty tuple. We want to
explicitly return None for testing purposes.

aif/utils/__init__.py

@@ -15,7 +15,7 @@ from . import hash_handler
 def checkMounted(devpath):
     if devpath in [p.device for p in psutil.disk_partitions(all = True)]:
         raise RuntimeError('{0} is mounted; we are cowardly refusing to destructive operations on it'.format(devpath))
-    return()
+    return(None)
 
 
 def collapseKeys(d, keylist = None):

aif/utils/file_handler.py

@@ -40,4 +40,4 @@ class Directory(object):
                     self.dirs.append(dirs)
         self.dirs.sort()
         self.files.sort()
-        return()
+        return(None)

aif/utils/gpg_handler.py

@@ -30,7 +30,7 @@ class GPG(object):
             self.primary_key = self.createKey('AIF-NG File Verification Key', sign = True, force = True)
         else:
             self.primary_key = self.getKey(self.primary_key, secret = True)
-        return()
+        return(None)
 
     def clean(self):
         # This is mostly just to cleanup the stuff we did before.
@@ -39,7 +39,7 @@ class GPG(object):
             self.primary_key = None
             shutil.rmtree(self.homedir)
         self.gpg = None
-        return()
+        return(None)
 
     def createKey(self, userid, *args, **kwargs):
         # algorithm=None, expires_in=0, expires=True, sign=False, encrypt=False, certify=False,
@@ -85,7 +85,7 @@ class GPG(object):
             except gpg.errors.KeyNotFound:
                 key = None
             return(key)
-        return()
+        return(None)
 
     def getKeyFile(self, keyfile, keyring_import = False):
         keyfile = os.path.abspath(os.path.expanduser(keyfile))
@@ -115,7 +115,7 @@ class GPG(object):
             if not isinstance(keydata, list):
                 keydata = [keydata]
             self.gpg.op_import_keys(keydata)
-        return()
+        return(None)
 
     def verifyData(self, data, keys = None, strict = False, detached = None, *args, **kwargs):
         results = {}