diff --git a/learnware/__init__.py b/learnware/__init__.py
index eed5dde..b7fb924 100644
--- a/learnware/__init__.py
+++ b/learnware/__init__.py
@@ -1,4 +1,4 @@
-__version__ = "0.2.0.5"
+__version__ = "0.2.0.6"
 
 import os
 import json
diff --git a/learnware/client/package_utils.py b/learnware/client/package_utils.py
index 2312661..5ece653 100644
--- a/learnware/client/package_utils.py
+++ b/learnware/client/package_utils.py
@@ -30,7 +30,7 @@ def parse_pip_requirement(line: str):
 
     line = line.strip()
     if len(line) == 0 or line[0] in ("#", "-"):
-        return None
+        return None, None
 
     package_name, package_version = line, line
     for split_ch in ("=", ">", "<", "!", "~", " ", "="):
diff --git a/learnware/market/heterogeneous/__init__.py b/learnware/market/heterogeneous/__init__.py
index e7ab916..df0ad39 100644
--- a/learnware/market/heterogeneous/__init__.py
+++ b/learnware/market/heterogeneous/__init__.py
@@ -1,2 +1,12 @@
-from .organizer import HeteroMapTableOrganizer
-from .searcher import HeteroSearcher
+from ...utils import is_torch_available
+from ...logger import get_module_logger
+
+logger = get_module_logger("market_hetero")
+
+if not is_torch_available(verbose=False):
+    HeteroMapTableOrganizer = None
+    HeteroSearcher = None
+    logger.error("HeteroMapTableOrganizer and HeteroSearcher are not available because 'torch' is not installed!")
+else:
+    from .organizer import HeteroMapTableOrganizer
+    from .searcher import HeteroSearcher
diff --git a/learnware/market/heterogeneous/searcher.py b/learnware/market/heterogeneous/searcher.py
index f261703..7194f9c 100644
--- a/learnware/market/heterogeneous/searcher.py
+++ b/learnware/market/heterogeneous/searcher.py
@@ -1,11 +1,9 @@
-import traceback
-from typing import Tuple, List
+from typing import Optional
 
 from .utils import is_hetero
 from ..base import BaseUserInfo, SearchResults
 from ..easy import EasySearcher
 from ..utils import parse_specification_type
-from ...learnware import Learnware
 from ...logger import get_module_logger
 
 
@@ -14,7 +12,7 @@ logger = get_module_logger("hetero_searcher")
 
 class HeteroSearcher(EasySearcher):
     def __call__(
-        self, user_info: BaseUserInfo, check_status: int = None, max_search_num: int = 5, search_method: str = "greedy"
+        self, user_info: BaseUserInfo, check_status: Optional[int] = None, max_search_num: int = 5, search_method: str = "greedy"
     ) -> SearchResults:
         """Search learnwares based on user_info from learnwares with check_status.
            Employs heterogeneous learnware search if specific requirements are met, otherwise resorts to homogeneous search methods.