diff --git a/learnware/client/container.py b/learnware/client/container.py
index e0a19a5..6d67e0e 100644
--- a/learnware/client/container.py
+++ b/learnware/client/container.py
@@ -3,7 +3,6 @@ import docker
 import pickle
 import atexit
 import tarfile
-import zipfile
 import tempfile
 import shortuuid
 from concurrent.futures import ThreadPoolExecutor
diff --git a/learnware/client/learnware_client.py b/learnware/client/learnware_client.py
index b06663e..a5d20b3 100644
--- a/learnware/client/learnware_client.py
+++ b/learnware/client/learnware_client.py
@@ -14,7 +14,7 @@ from typing import Union, List
 from ..config import C
 from .. import learnware
 from .container import LearnwaresContainer
-from ..market import BaseChecker, EasySemanticChecker, EasyStatChecker, CondaChecker
+from ..market import BaseChecker, EasySemanticChecker, EasyStatChecker
 from ..logger import get_module_logger
 from ..specification import Specification
 from ..learnware import get_learnware_from_dirpath
@@ -389,6 +389,8 @@ class LearnwareClient:
 
     @staticmethod
     def _check_stat_specification(learnware):
+        from ..market import CondaChecker
+
         stat_checker = CondaChecker(inner_checker=EasyStatChecker())
         return stat_checker(learnware) != BaseChecker.INVALID_LEARNWARE
 
diff --git a/learnware/market/classes.py b/learnware/market/classes.py
index 27c5f1b..8fa9ab7 100644
--- a/learnware/market/classes.py
+++ b/learnware/market/classes.py
@@ -1,4 +1,4 @@
-from .base import BaseChecker, BaseOrganizer
+from .base import BaseChecker
 from ..learnware import Learnware
 from ..client.container import LearnwaresContainer
 from ..logger import get_module_logger