diff --git a/src/modules/graphics.lua b/src/modules/graphics.lua
index eca0c9e..87e8d4f 100644
--- a/src/modules/graphics.lua
+++ b/src/modules/graphics.lua
@@ -21,7 +21,7 @@ return function(update_freq, config, common, width, point)
    i_o.assert_exe_exists(NVIDIA_EXE)
 
    local mk_query_cmd = function(props)
-      return string.format(
+      return __string_format(
          '%s --query-gpu=%s --format=csv,noheader,nounits',
          NVIDIA_EXE,
          pure.collapse(props, ',')
@@ -99,13 +99,13 @@ return function(update_freq, config, common, width, point)
                mod_state.gpu_utilization,
                mod_state.vid_utilization
                = __string_match(nvidia_settings_glob, NV_REGEX)
-            mod_state.gpu_frequency = tonumber(mod_state.gpu_frequency)
+            mod_state.gpu_frequency = __tonumber(mod_state.gpu_frequency)
             mod_state.error = false
          end
          -- query total memory if we need it (do this here so we don't turn on
          -- the gpu every time we start conky)
          if mod_state.total_memory == 0 and config.show_mem_util then
-            mod_state.total_memory = tonumber(i_o.execute_cmd(mk_query_cmd({'memory.total'})))
+            mod_state.total_memory = __tonumber(i_o.execute_cmd(mk_query_cmd({'memory.total'})))
          end
       elseif is_active then
          mod_state.error = false