Use PackageMetadata instead of Message

piplicenses.py

@@ -39,9 +39,9 @@
 from enum import Enum, auto
 from functools import partial
 from importlib import metadata as importlib_metadata
-from importlib.metadata import Distribution
+from importlib.metadata import Distribution, PackageMetadata
 from pathlib import Path
-from typing import TYPE_CHECKING, cast
+from typing import cast
 
 import tomli
 from prettytable import ALL as RULE_ALL
@@ -50,10 +50,6 @@
 from prettytable import NONE as RULE_NONE
 from prettytable import PrettyTable
 
-if TYPE_CHECKING:  # pragma: no cover
-    from email.message import Message
-
-
 open = open  # allow monkey patching
 
 __pkgname__ = "pip-licenses"
@@ -96,7 +92,7 @@
 )
 
 
-def extract_homepage(metadata: Message) -> str | None:
+def extract_homepage(metadata: PackageMetadata) -> str | None:
     """Extracts the homepage attribute from the package metadata.
 
     Not all python packages have defined a home-page attribute.
@@ -151,7 +147,7 @@ def normalize_pkg_name(pkg_name: str) -> str:
     return PATTERN_DELIMITER.sub("-", pkg_name).lower()
 
 
-METADATA_KEYS: dict[str, list[Callable[[Message], str | None]]] = {
+METADATA_KEYS: dict[str, list[Callable[[PackageMetadata], str | None]]] = {
     "home-page": [extract_homepage],
     "author": [
         lambda metadata: metadata.get("author"),
@@ -235,9 +231,7 @@ def get_pkg_info(pkg: Distribution) -> dict[str, str | list[str]]:
         for field_name, field_selector_fns in METADATA_KEYS.items():
             value = None
             for field_selector_fn in field_selector_fns:
-                # Type hint of `Distribution.metadata` states `PackageMetadata`
-                # but it's actually of type `email.Message`
-                value = field_selector_fn(metadata)  # type: ignore
+                value = field_selector_fn(metadata)
                 if value:
                     break
             pkg_info[field_name] = value or LICENSE_UNKNOWN