Update src/vfb_connect/cross_server_tools.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: Robbie1977

src/vfb_connect/cross_server_tools.py

@@ -834,7 +834,9 @@ def get_expressed_genes_by_cell_and_gene_type(self, cell_type, gene_type, no_sub
 
         r = self.nc.commit_list([query])
         if not r:
-            warnings.warn("No results returned")
+            warnings.warn(
+                f"No results returned in get_expressed_genes_by_cell_and_gene_type for cell_type={cell_type} and gene_type={gene_type}"
+            )
             return False
         dc = dict_cursor(r)
         if return_dataframe: