Import 'reduce' for Python 3

gracedb/alerts/recipients.py

+try:
+    from functools import reduce
+except ImportError:  # python < 3
+    pass
+
 from django.conf import settings
 from django.db.models import Q
 

gracedb/api/tests/utils.py

 from copy import deepcopy
+try:
+    from functools import reduce
+except ImportError:  # python < 3
+    pass
 try:
     from unittest import mock
 except ImportError:  # python < 3

gracedb/search/query/events.py

@@ -15,6 +15,10 @@ from pyparsing import Word, nums, Literal, CaselessLiteral, delimitedList, \
     oneOf, stringStart,  stringEnd, FollowedBy, ParseResults, ParseException, \
     CaselessKeyword
 import pytz
+try:
+    from functools import reduce
+except ImportError:  # python < 3
+    pass
 
 from django.db.models import Q
 from django.db.models.query import QuerySet