BF: Restore behaviour of accepting vids=None from processing functions

ukbparse/processing.py

@@ -138,6 +138,10 @@ def runProcess(proc, dtable, vids):
     addvids = []
     addmeta = []
 
+    def expand(res, length):
+        if res is None: return [None] * length
+        else:           return res
+
     for result in results:
         if result is None:
             continue
@@ -150,20 +154,20 @@ def runProcess(proc, dtable, vids):
             # series/vids to add
             if len(result) == 2:
                 add    .extend(result[0])
-                addvids.extend(result[1])
-                addmeta.extend([None] * len(result[1]))
+                addvids.extend(expand(result[1], len(result[0])))
+                addmeta.extend(expand(None,      len(result[0])))
 
             # columns to remove, and
             # series/vids to add
             elif len(result) in (3, 4):
 
-                if len(result) == 3: meta = [None] * len(result[1])
-                else:                meta = result[3]
+                if len(result) == 3:
+                    result = list(result) + [None]
 
                 remove .extend(result[0])
                 add    .extend(result[1])
-                addvids.extend(result[2])
-                addmeta.extend(meta)
+                addvids.extend(expand(result[2], len(result[1])))
+                addmeta.extend(expand(result[3], len(result[1])))
             else:
                 raise error