Add nullcheck for var_name in handle_binary_ops

Author: r41k0u

pythonbpf/binary_ops.py

@@ -64,6 +64,9 @@ def handle_binary_op_impl(rval, builder, local_sym_tab):
 
 def handle_binary_op(rval, builder, var_name, local_sym_tab):
     result = handle_binary_op_impl(rval, builder, local_sym_tab)
-    if var_name in local_sym_tab:
+    if var_name and var_name in local_sym_tab:
+        logger.info(
+            f"Storing result {result} into variable {local_sym_tab[var_name].var}"
+        )
         builder.store(result, local_sym_tab[var_name].var)
     return result, result.type