diff --git a/kiwi_scp/executable.py b/kiwi_scp/executable.py
index f2646cc..48168d1 100644
--- a/kiwi_scp/executable.py
+++ b/kiwi_scp/executable.py
@@ -28,7 +28,7 @@ class Executable:
     def exe_file(self) -> Optional[Path]:
         return self.__find_exe_file(self.exe_name)
 
-    def __build_cmd(self, args, kwargs) -> List[Path, Any, ...]:
+    def __build_cmd(self, args, kwargs) -> List:
         cmd = [self.exe_file, *args]
 
         _logger.debug(f"Executable cmd{cmd}, kwargs{kwargs}")
@@ -40,7 +40,7 @@ class Executable:
             **kwargs
         )
 
-    def Popen(self, process_args, **kwargs) -> subprocess.Popen[str]:
+    def Popen(self, process_args, **kwargs) -> subprocess.Popen:
         return subprocess.Popen(
             self.__build_cmd(process_args, kwargs),
             **kwargs
diff --git a/kiwi_scp/rootkit.py b/kiwi_scp/rootkit.py
index a3c7937..7332c43 100644
--- a/kiwi_scp/rootkit.py
+++ b/kiwi_scp/rootkit.py
@@ -1,86 +1,78 @@
-# system
+import functools
 import logging
-import os
 import subprocess
+from pathlib import Path
+from typing import Optional, TypeVar, Union, List
+
+import attr
 
-# local
 from ._constants import IMAGES_DIRECTORY_NAME, LOCAL_IMAGES_NAME, DEFAULT_IMAGE_NAME
 from .executable import Executable
 
+_logger = logging.getLogger(__name__)
+
+PSL = TypeVar("PSL", Union[Path, str], List[Union[Path, str]])
+
+
+def prefix_path(path: PSL, prefix: Path = Path("/mnt")) -> PSL:
+    if isinstance(path, Path):
+        return prefix.joinpath(path.absolute())
 
-def _prefix_path(prefix, path):
     if isinstance(path, str):
-        abs_path = os.path.abspath(path)
-        return os.path.realpath(f"{prefix}/{abs_path}")
+        return prefix_path(Path(path), prefix)
 
     elif isinstance(path, list):
-        return [_prefix_path(prefix, p) for p in path]
-
-
-def prefix_path_mnt(path):
-    return _prefix_path('/mnt/', path)
-
-
-def _image_name(image_tag):
-    if image_tag is not None:
-        return f"{LOCAL_IMAGES_NAME}:{image_tag}"
-    else:
-        return DEFAULT_IMAGE_NAME
+        return [prefix_path(prefix, p) for p in path]
 
 
+@attr.s
 class Rootkit:
-    class __Rootkit:
-        __image_tag = None
+    image_tag: str = attr.ib()
 
-        def __init__(self, image_tag=None):
-            self.__image_tag = image_tag
+    @staticmethod
+    @functools.lru_cache(maxsize=None)
+    def __image_name(image_tag: Optional[str]) -> str:
+        if image_tag is not None:
+            return f"{LOCAL_IMAGES_NAME}:{image_tag}"
+        else:
+            return DEFAULT_IMAGE_NAME
 
-        def __exists(self):
-            ps = Executable('docker').run([
-                'images',
-                '--filter', f"reference={_image_name(self.__image_tag)}",
-                '--format', '{{.Repository}}:{{.Tag}}'
-            ], stdout=subprocess.PIPE)
+    @staticmethod
+    @functools.lru_cache(maxsize=None)
+    def __exists(image_tag: str) -> bool:
+        ps = Executable('docker').run([
+            'images',
+            '--filter', f"reference={Rootkit.__image_name(image_tag)}",
+            '--format', '{{.Repository}}:{{.Tag}}'
+        ], stdout=subprocess.PIPE)
 
-            return str(ps.stdout, 'utf-8').strip() == _image_name(self.__image_tag)
+        return str(ps.stdout, 'utf-8').strip() == Rootkit.__image_name(image_tag)
+
+    def __build_image(self) -> None:
+        if Rootkit.__exists(self.image_tag):
+            _logger.info(f"Using image {Rootkit.__image_name(self.image_tag)}")
+        else:
+            if self.image_tag is None:
+                _logger.info(f"Pulling image {Rootkit.__image_name(self.image_tag)}")
+                Executable('docker').run([
+                    'pull', Rootkit.__image_name(self.image_tag)
+                ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
 
-        def __build_image(self):
-            if self.__exists():
-                logging.info(f"Using image {_image_name(self.__image_tag)}")
             else:
-                if self.__image_tag is None:
-                    logging.info(f"Pulling image {_image_name(self.__image_tag)}")
-                    Executable('docker').run([
-                        'pull', _image_name(self.__image_tag)
-                    ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+                _logger.info(f"Building image {Rootkit.__image_name(self.image_tag)}")
+                Executable('docker').run([
+                    'build',
+                    '-t', Rootkit.__image_name(self.image_tag),
+                    '-f', f"{IMAGES_DIRECTORY_NAME}/{self.image_tag}.Dockerfile",
+                    f"{IMAGES_DIRECTORY_NAME}"
+                ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
 
-                else:
-                    logging.info(f"Building image {_image_name(self.__image_tag)}")
-                    Executable('docker').run([
-                        'build',
-                        '-t', _image_name(self.__image_tag),
-                        '-f', f"{IMAGES_DIRECTORY_NAME}/{self.__image_tag}.Dockerfile",
-                        f"{IMAGES_DIRECTORY_NAME}"
-                    ], stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
-
-        def run(self, process_args, **kwargs):
-            self.__build_image()
-            Executable('docker').run([
-                'run', '--rm',
-                '-v', '/:/mnt',
-                '-u', 'root',
-                _image_name(self.__image_tag),
-                *process_args
-            ], **kwargs)
-
-    __image_tag = None
-    __instances = {}
-
-    def __init__(self, image_tag=None):
-        self.__image_tag = image_tag
-
-        if _image_name(self.__image_tag) not in Rootkit.__instances:
-            Rootkit.__instances[_image_name(self.__image_tag)] = Rootkit.__Rootkit(image_tag)
-
-    def __getattr__(self, item):
-        return getattr(self.__instances[_image_name(self.__image_tag)], item)
+    def run(self, process_args, **kwargs):
+        self.__build_image()
+        Executable('docker').run([
+            'run', '--rm',
+            '-v', '/:/mnt',
+            '-u', 'root',
+            Rootkit.__image_name(self.image_tag),
+            *process_args
+        ], **kwargs)