# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1423428770 -3600
# Node ID cc6138b8d1728a7dabc965dcc5b0cf56dab299fe
# Parent  da7fd03fd2ab2402fbc396a30ecebd800068eca8
Return None from get_datetime if the incoming value is a false value.

diff -r da7fd03fd2ab -r cc6138b8d172 imiptools/dates.py
--- a/imiptools/dates.py	Sun Feb 08 20:18:08 2015 +0100
+++ b/imiptools/dates.py	Sun Feb 08 21:52:50 2015 +0100
@@ -132,6 +132,9 @@
     the 'attr' mapping (if specified) to control the conversion.
     """
 
+    if not value:
+        return None
+
     if len(value) > 9 and (not attr or attr.get("VALUE") in (None, "DATE-TIME")):
         m = match_datetime_icalendar(value)
         if m: