#18424: PEP8ify the tense of the sum docstring.
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index cdc9080..d22dca2 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2434,9 +2434,9 @@
 PyDoc_STRVAR(sum_doc,
 "sum(sequence[, start]) -> value\n\
 \n\
-Returns the sum of a sequence of numbers (NOT strings) plus the value\n\
+Return the sum of a sequence of numbers (NOT strings) plus the value\n\
 of parameter 'start' (which defaults to 0).  When the sequence is\n\
-empty, returns start.");
+empty, return start.");
 
 
 static PyObject *