Fix documentation typos
diff --git a/lib/predictionio/client.rb b/lib/predictionio/client.rb
index 4ef2992..0b81135 100644
--- a/lib/predictionio/client.rb
+++ b/lib/predictionio/client.rb
@@ -505,8 +505,8 @@
     # See #aget_itemrec_top_n for a description of special argument handling.
     #
     # call-seq:
-    # aget_itemrec_top_n(engine, n, params = {})
-    # aget_itemrec_top_n(async_response)
+    # get_itemrec_top_n(engine, n, params = {})
+    # get_itemrec_top_n(async_response)
     def get_itemrec_top_n(*args)
       uid_or_res = args[0]
       if uid_or_res.is_a?(PredictionIO::AsyncResponse)
@@ -565,8 +565,8 @@
     # See #aget_itemrank_ranked for a description of special argument handling.
     #
     # call-seq:
-    # aget_itemrank_ranked(engine, n, params = {})
-    # aget_itemrank_ranked(async_response)
+    # get_itemrank_ranked(engine, n, params = {})
+    # get_itemrank_ranked(async_response)
     def get_itemrank_ranked(*args)
       uid_or_res = args[0]
       if uid_or_res.is_a?(PredictionIO::AsyncResponse)
@@ -633,8 +633,8 @@
     # See #aget_itemsim_top_n for a description of special argument handling.
     #
     # call-seq:
-    # aget_itemsim_top_n(engine, iid, n, params = {})
-    # aget_itemsim_top_n(async_response)
+    # get_itemsim_top_n(engine, iid, n, params = {})
+    # get_itemsim_top_n(async_response)
     def get_itemsim_top_n(*args)
       uid_or_res = args[0]
       if uid_or_res.is_a?(PredictionIO::AsyncResponse)