upgrade 7z to 7zz (#1005)

kindlecomicconverter/shared.py

@@ -18,7 +18,6 @@
 # PERFORMANCE OF THIS SOFTWARE.
 #
 
-from functools import lru_cache
 import os
 from html.parser import HTMLParser
 import subprocess
@@ -131,19 +130,6 @@ def dependencyCheck(level):
         print('ERROR: ' + ', '.join(missing) + ' is not installed!')
         sys.exit(1)
 
-@lru_cache
-def available_archive_tools():
-    available = []
-
-    for tool in ['tar', '7z', 'unar', 'unrar']:
-        try:
-            subprocess_run([tool], stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
-            available.append(tool)
-        except (FileNotFoundError, subprocess.CalledProcessError):
-            pass
-    
-    return available
-
 def subprocess_run(command, **kwargs):
     if (os.name == 'nt'):
         kwargs.setdefault('creationflags', subprocess.CREATE_NO_WINDOW)