fix: fix the lint check errors of the main branch (#403)

tests/unit/prompt_enhancer/graph/test_builder.py

@@ -6,7 +6,6 @@ from unittest.mock import patch, MagicMock
 
 from src.prompt_enhancer.graph.builder import build_graph
 from src.prompt_enhancer.graph.state import PromptEnhancerState
-from src.config.report_style import ReportStyle
 
 
 class TestBuildGraph:
@@ -48,7 +47,7 @@ class TestBuildGraph:
         mock_state_graph.return_value = mock_builder
         mock_builder.compile.return_value = mock_compiled_graph
 
-        result = build_graph()
+        build_graph()
 
         # Verify the correct node function was added
         mock_builder.add_node.assert_called_once_with("enhancer", mock_enhancer_node)

tests/unit/prompt_enhancer/graph/test_state.py

@@ -1,7 +1,6 @@
 # Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 # SPDX-License-Identifier: MIT
 
-import pytest
 from src.prompt_enhancer.graph.state import PromptEnhancerState
 from src.config.report_style import ReportStyle