Updated parsing IO class statistics for cache/core

Signed-off-by: Daniel Madej <daniel.madej@intel.com>

test/functional/api/cas/cache.py

@@ -3,14 +3,14 @@
 # SPDX-License-Identifier: BSD-3-Clause-Clear
 #
 
-from api.cas.cli import *
-from api.cas.casadm_parser import *
-from test_utils.os_utils import *
 from api.cas.cache_config import *
-from storage_devices.device import Device
-from core.test_run import TestRun
 from api.cas.casadm_params import *
+from api.cas.casadm_parser import *
+from api.cas.cli import *
 from api.cas.statistics import CacheStats, IoClassStats
+from core.test_run import TestRun
+from storage_devices.device import Device
+from test_utils.os_utils import *
 
 
 class Cache:
@@ -99,7 +99,7 @@ class Cache:
                                 percentage_val: bool = False):
         stats = get_statistics(self.cache_id, None, io_class_id,
                                stat_filter, percentage_val)
-        return IoClassStats(stats)
+        return IoClassStats(stats, for_cache=True)
 
     def get_statistics(self,
                        stat_filter: List[StatsFilter] = None,