FIX update audio

setting "end" to an empty field was resulting in the field not being
changed.

larigira/timeform_base.py

@@ -1,16 +1,10 @@
 import logging
-
 from datetime import datetime
-from pytimeparse.timeparse import timeparse
 
 from flask_wtf import Form
-from wtforms import (
-    StringField,
-    validators,
-    SubmitField,
-    SelectMultipleField,
-    ValidationError,
-)
+from pytimeparse.timeparse import timeparse
+from wtforms import (SelectMultipleField, StringField, SubmitField,
+                     ValidationError, validators)
 
 from larigira.formutils import EasyDateTimeField
 
@@ -123,6 +117,6 @@ def frequencyalarm_receive(form):
         obj["start"] = int(form.start.data.strftime("%s"))
     else:
         obj["start"] = 0
-    if form.end.data:
-        obj["end"] = int(form.end.data.strftime("%s"))
+
+    obj["end"] = int(form.end.data.strftime("%s")) if form.end.data else None
     return obj