diff --git a/nvchecker/lib/packaging_version.py b/nvchecker/lib/packaging_version.py
index 82b697b..1e5730e 100644
--- a/nvchecker/lib/packaging_version.py
+++ b/nvchecker/lib/packaging_version.py
@@ -91,11 +91,10 @@ class NegativeInfinityType(object):
 
 
 NegativeInfinity = NegativeInfinityType()
+
 if TYPE_CHECKING:  # pragma: no cover
     from typing import Callable, Iterator, List, Optional, SupportsInt, Tuple, Union
 
-    from ._structures import InfinityType, NegativeInfinityType
-
     InfiniteTypes = Union[InfinityType, NegativeInfinityType]
     PrePostDevType = Union[InfiniteTypes, Tuple[str, int]]
     SubLocalType = Union[InfiniteTypes, int, str]
diff --git a/nvchecker/sortversion.py b/nvchecker/sortversion.py
index 4903e99..d8209ed 100644
--- a/nvchecker/sortversion.py
+++ b/nvchecker/sortversion.py
@@ -1,5 +1,5 @@
 # MIT licensed
-# Copyright (c) 2013-2017 lilydjwg <lilydjwg@gmail.com>, et al.
+# Copyright (c) 2013-2021 lilydjwg <lilydjwg@gmail.com>, et al.
 
 '''
 Sort versions using deprecated pkg_resource / packaging.parse_version or pyalpm.vercmp
@@ -7,11 +7,10 @@ Sort versions using deprecated pkg_resource / packaging.parse_version or pyalpm.
 
 __all__ = ["sort_version_keys"]
 
-from functools import cmp_to_key
-
 from .lib.packaging_version import parse as parse_version
 try:
   import pyalpm
+  from functools import cmp_to_key
   vercmp = cmp_to_key(pyalpm.vercmp)
   vercmp_available = True
 except ImportError:
diff --git a/nvchecker/tools.py b/nvchecker/tools.py
index f4de150..60c87d5 100644
--- a/nvchecker/tools.py
+++ b/nvchecker/tools.py
@@ -107,7 +107,7 @@ def cmp() -> None:
         if args.sort != "none" and oldver is not None and newver is not None:
           from .sortversion import sort_version_keys
           version = sort_version_keys[args.sort]
-          if version(oldver) > version(newver):
+          if version(oldver) > version(newver): # type: ignore
             arrow = f'{c.red}<-{c.normal}'
             if args.newer:
               continue