Fix wrong doc function name
diff --git a/option.go b/option.go
index 8270a22..ea09fb4 100644
--- a/option.go
+++ b/option.go
@@ -179,7 +179,7 @@
 	return option.isSet
 }
 
-// IsSet returns true if option has been set via the default option tag
+// IsSetDefault returns true if option has been set via the default option tag
 func (option *Option) IsSetDefault() bool {
 	return option.isSetDefault
 }