Apply suggestion from @JohannesGaessler

Co-authored-by: Johannes Gäßler <johannesg@5d6.de>

Author: yeahdongcn

scripts/compare-llama-bench.py

@@ -327,10 +327,12 @@ def __init__(self, tool: str = "llama-bench"):
             self.table_name = "test"
             db_fields = LLAMA_BENCH_DB_FIELDS
             db_types = LLAMA_BENCH_DB_TYPES
-        else:  # test-backend-ops
+        elif self.tool == "test-backend-ops":
             self.table_name = "test_backend_ops"
             db_fields = TEST_BACKEND_OPS_DB_FIELDS
             db_types = TEST_BACKEND_OPS_DB_TYPES
+        else:
+            assert False
 
         self.cursor.execute(f"CREATE TABLE {self.table_name}({', '.join(' '.join(x) for x in zip(db_fields, db_types))});")
 
@@ -356,8 +358,10 @@ def builds_timestamp(self, reverse: bool = False) -> Union[Iterator[tuple], Sequ
     def get_rows(self, properties: list[str], hexsha8_baseline: str, hexsha8_compare: str) -> Sequence[tuple]:
         if self.tool == "llama-bench":
             return self._get_rows_llama_bench(properties, hexsha8_baseline, hexsha8_compare)
-        else:  # test-backend-ops
+        elif self.tool == "test-backend-ops":
             return self._get_rows_test_backend_ops(properties, hexsha8_baseline, hexsha8_compare)
+        else:
+            assert False
 
     def _get_rows_llama_bench(self, properties: list[str], hexsha8_baseline: str, hexsha8_compare: str) -> Sequence[tuple]:
         select_string = ", ".join(
@@ -1041,8 +1045,10 @@ def make_axes(num_groups, max_cols=2, base_size=(8, 4)):
             # Determine y-axis label based on tool type
             if tool_type == "llama-bench":
                 y_label = "Tokens per second (t/s)"
-            else:  # test-backend-ops
+            elif tool_type == "test-backend-ops":
                 y_label = metric_name
+            else:
+                assert False
 
             ax.set_xlabel(plot_x_label, fontsize=12, fontweight='bold')
             ax.set_ylabel(y_label, fontsize=12, fontweight='bold')