diff --git a/vobject/ics_diff.py b/vobject/ics_diff.py
index c119c99..c532d4f 100644
--- a/vobject/ics_diff.py
+++ b/vobject/ics_diff.py
@@ -138,8 +138,8 @@ def processComponentPair(leftComp, rightComp):
         if len(differentContentLines) == 0 and len(differentComponents) == 0:
             return None
         else:
-            left = newFromBehavior(leftComp.name)
-            right = newFromBehavior(leftComp.name)
+            left = vobject.newFromBehavior(leftComp.name)
+            right = vobject.newFromBehavior(leftComp.name)
             # add a UID, if one existed, despite the fact that they'll always be
             # the same
             uid = leftComp.getChildValue('uid')
@@ -193,8 +193,8 @@ def main():
         ignore_dtstamp = options.ignore
         ics_file1, ics_file2 = args
         with open(ics_file1) as f, open(ics_file2) as g:
-            cal1 = readOne(f)
-            cal2 = readOne(g)
+            cal1 = vobject.readOne(f)
+            cal2 = vobject.readOne(g)
         deleteExtraneous(cal1, ignore_dtstamp=ignore_dtstamp)
         deleteExtraneous(cal2, ignore_dtstamp=ignore_dtstamp)
         prettyDiff(cal1, cal2)