Update app.py

app.py

@@ -54,7 +54,10 @@ def main(input_file_path, species):
     print(input_file_path)
     print(dir_path)
     print(model_loc)
-    
+
+    # Verify adata_path is not None
+    if adata_path is None or not os.path.exists(adata_path):
+        raise ValueError(f"Invalid adata_path: {adata_path}. Please check if the file exists.")
     
     # Construct the command
     command = [