Apply suggestion to src/main/java/gov/usgs/earthquake/nshmp/data/Sequences.java

src/main/java/gov/usgs/earthquake/nshmp/data/Sequences.java

@@ -103,7 +103,7 @@ class Sequences {
         .flatMap(XySequence::stream)
         .collect(Collectors.toMap(
             XyPoint::x,
-            (XyPoint xy) -> (double) xy.y(),
+            XyPoint::y,
             Double::sum,
             TreeMap::new));
     return XySequence.create(