diff --git a/internal/common/types.go b/internal/common/types.go
index 9edcc89..e1b5110 100644
--- a/internal/common/types.go
+++ b/internal/common/types.go
@@ -10,7 +10,10 @@ import (
 )
 
 type (
+	// PyTimeStamp is a python-style long nano timestamp
 	PyTimestamp time.Time
+
+	// KeepZero is a special float that keeps the trailing zero on marshal
 	KeepZero    float64
 )