diff --git a/core/src/main/scala/sttp/model/sse/ServerSentEvent.scala b/core/src/main/scala/sttp/model/sse/ServerSentEvent.scala
index 9c4ba2af..34020d44 100644
--- a/core/src/main/scala/sttp/model/sse/ServerSentEvent.scala
+++ b/core/src/main/scala/sttp/model/sse/ServerSentEvent.scala
@@ -3,11 +3,11 @@ package sttp.model.sse
 import scala.util.Try
 
 case class ServerSentEvent(
-    data: Option[String] = None,
-    eventType: Option[String] = None,
-    id: Option[String] = None,
-    retry: Option[Int] = None
-)
+                            data: Option[String] = None,
+                            eventType: Option[String] = None,
+                            id: Option[String] = None,
+                            retry: Option[Int] = None
+                          )
 
 object ServerSentEvent {
   // https://html.spec.whatwg.org/multipage/server-sent-events.html
@@ -25,7 +25,7 @@ object ServerSentEvent {
   }
 
   def composeSSE(sse: ServerSentEvent): String = {
-    val data = sse.data.map(_.split("\n")).map(_.map(line => Some(s"data: $line"))).getOrElse(Array.empty)
+    val data = sse.data.map(_.split("\n")).map(_.map(line => Some(s"data: $line"))).getOrElse(Array.empty[Option[String]])
     val event = sse.eventType.map(event => s"event: $event")
     val id = sse.id.map(id => s"id: $id")
     val retry = sse.retry.map(retryCount => s"retry: $retryCount")
@@ -34,8 +34,8 @@ object ServerSentEvent {
 
   private def combineData(event: ServerSentEvent, newData: String): ServerSentEvent = {
     event match {
-      case e @ ServerSentEvent(Some(oldData), _, _, _) => e.copy(data = Some(s"$oldData\n$newData"))
-      case e @ ServerSentEvent(None, _, _, _)          => e.copy(data = Some(newData))
+      case e@ServerSentEvent(Some(oldData), _, _, _) => e.copy(data = Some(s"$oldData\n$newData"))
+      case e@ServerSentEvent(None, _, _, _) => e.copy(data = Some(newData))
     }
   }