diff --git a/dataset.go b/dataset.go
index 51b836f..3a29efb 100644
--- a/dataset.go
+++ b/dataset.go
@@ -40,6 +40,9 @@ func (m *DataSet) FieldByType(dsType DataSetType) (interface{}, error) {
 
 	switch dsType {
 	case DataSetType_KEYWORD, DataSetType_SENTIMENT:
+		if m.Keyword == nil {
+			return nil, nil
+		}
 		return m.Keyword, nil
 	}
 
diff --git a/dataset_test.go b/dataset_test.go
index c76f7fe..360cf8f 100644
--- a/dataset_test.go
+++ b/dataset_test.go
@@ -21,7 +21,7 @@ func testDS(t *testing.T, ds *DataSet, expectNil bool) {
 		}
 
 		if i != nil && expectNil {
-			t.Errorf("got unexpected nil dataset field %v", i)
+			t.Errorf("got unexpected nil dataset field %#v", i)
 		}
 
 		if expectNil {