Fix date container builder.

src/main/kotlin/builders/DateContainerBuilder.kt

@@ -35,12 +35,12 @@ class DateContainerBuilder(private val containedIds: List<String>) : IFieldBuild
         }
         val qualifier = when (val value = jsonObject["dateQualifier"]) {
             is String -> listOf(value)
-            is JsonArray<*> -> value.mapNotNull { value as String? }
+            is JsonArray<*> -> value.mapNotNull { it as String? }
             else -> emptyList()
         }
         val certainty = when (val value = jsonObject["certainty"]) {
             is String -> listOf(value)
-            is JsonArray<*> -> value.mapNotNull { value as String? }
+            is JsonArray<*> -> value.mapNotNull { it as String? }
             else -> emptyList()
         }
         val facetList = when (jsonObject["@type"] as String) {