Allow empty statement batches

Author: kelvinqian00

src/xapi_schema/spec.cljc

@@ -1326,8 +1326,13 @@
                    (some-> s :statement/object :statement-ref/objectType)
                    true)))))
 
+;; Statement batches in general, e.g. when being inserted into an LRS, should
+;; allow empty arrays.
+
+;; Statement batches being retrieved from an LRS should always be non-emtpy.
+
 (s/def ::statements
-  (s/coll-of ::statement :into [] :min-count 1))
+  (s/coll-of ::statement :into []))
 
 (s/def ::lrs-statements
   (s/coll-of ::lrs-statement :into [] :min-count 1))