use bench_command instead of bench_func

Author: Fidget-Spinner

pyperformance/benchmarks/bm_mypy_types.py

@@ -12,20 +12,11 @@
 
 from mypy.main import main
 
-
-def typecheck_targets(targets):
-    with open(os.devnull, 'w') as devnull:
-        try:
-            main(None, devnull, devnull, targets)
-        except SystemExit:
-            pass
-
-
 if __name__ == '__main__':
     runner = pyperf.Runner()
     runner.metadata['description'] = ('Mypy benchmark: '
                                       'type-check mypy/types.py')
     target_path = os.path.join(os.path.dirname(__file__), 'data',
                                'bm_mypy_target.py')
-    runner.bench_func('mypy_types', typecheck_targets, [target_path])
+    runner.bench_command('mypy_types', ['mypy', target_path])