implement lazy declaration at begin of documentation when caching is active

src/environments/groupthm/groupthm.dtx

@@ -2276,17 +2276,9 @@
   { \@@_Declarator: GroupedTheorem }
   { s O{} m }
   {
-    \bool_if:nTF
+    \bool_if:NTF \g_@@_cache_bool
       {
-        \g_@@_cache_bool
-        &&
-        \int_compare_p:n
-          {
-            \g_@@_cache_version_aux_int < \g_@@_cache_version_document_int
-          }
-      }
-      {
-        \hook_gput_code:nnn {@@/lazy} { groupthm }
+        \hook_gput_code:nnn {@@/definelazy} { groupthm }
       }
       {
         \use:n
@@ -2659,6 +2651,30 @@
 %
 %
 % \subsection{Caching}
+%
+% 
+% 
+%
+%    \begin{macrocode}
+  \hook_gput_code:nnn { begindocument } { groupthm }
+  {
+    \bool_if:nTF
+      {
+        \g_@@_cache_bool
+        &&
+        \int_compare_p:n
+          {
+            \g_@@_cache_version_aux_int < \g_@@_cache_version_document_int
+          }
+      }
+      {
+        \hook_use_once:n { @@ / define lazy }
+      }
+      {
+      }
+  }
+%    \end{macrocode}  
+% 
 % 
 % 
 %