diff --git a/themes/atomic/atomic.theme.bash b/themes/atomic/atomic.theme.bash
index 6a7819f5..8ac18dfd 100644
--- a/themes/atomic/atomic.theme.bash
+++ b/themes/atomic/atomic.theme.bash
@@ -27,8 +27,6 @@ Face="\342\230\273"
 ## Parsers ##
 #############
 
-isFunction() { [[ "$(declare -Ff "$1")" ]]; }
-
 ____atomic_top_left_parse() {
   ifs_old="${IFS}"
   IFS="|"
@@ -166,7 +164,7 @@ ___atomic_prompt_clock() {
 }
 
 ___atomic_prompt_battery() {
-  chk=$(isFunction battery_percentage && echo yes || echo no)
+  chk=$(command_exists battery_percentage && echo yes || echo no)
   [ "$chk" != "yes" ] || [ "${THEME_SHOW_BATTERY}" != "true" ] && return
   batp=$(battery_percentage)
   if [ "$batp" -eq 50 ] || [ "$batp" -gt 50 ]; then