diff --git a/generate-themes.nu b/generate-themes.nu
index ac6902c..816f51f 100755
--- a/generate-themes.nu
+++ b/generate-themes.nu
@@ -1,8 +1,8 @@
 #!/usr/bin/env nu
 
 def theme-to-nix [
-  theme: record, # The theme to convert to Nix.
-] -> nothing {
+  theme: record # The theme to convert to Nix.
+] {
   $theme
   | items { |key, value|
     let key = match $key {
diff --git a/visualize.nu b/visualize.nu
index 1e66a6a..76b8b57 100755
--- a/visualize.nu
+++ b/visualize.nu
@@ -2,8 +2,8 @@
 
 # Visualizes a theme in the terminal.
 def main [
-  theme: string, # The path to the theme to visualize.
-] -> nothing {
+  theme: string@"ls themes" # The path to the theme to visualize.
+] {
   if not ($env.COLORTERM | str contains "truecolor") {
     echo "your terminal emulator doesn't support truecolor, colors may be wrong\n"
   }