flags pkg : but im not convinced this is right

flags/flags.go

@@ -0,0 +1,24 @@
+package flags
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Flag string
+
+func (f Flag) Dash() string {
+	return fmt.Sprintf("--%s", f)
+}
+
+// prepend --flag to args if a flag isn't there:
+// allows trailing flags:
+// um tag foo --invert
+// becomes:
+// um tag --query foo --invert
+func PrependFlagToArgs(args []string, flag Flag) []string {
+	if len(args) >= 1 && !strings.HasPrefix(args[0], "-") {
+		args = append([]string{flag.Dash()}, args...)
+	}
+	return args
+}