[builder] make builder functional again

1 files changed, 11 insertions, 6 deletions

diff --git a/src/hydrilla/builder/piggybacking.py b/src/hydrilla/builder/piggybacking.py
index f732f3d..3e4084f 100644
--- a/src/hydrilla/builder/piggybacking.py
+++ b/src/hydrilla/builder/piggybacking.py
@@ -33,8 +33,9 @@ software system backends.
 # Enable using with Python 3.7.
 from __future__ import annotations
 
+import typing as t
+
 from pathlib import Path, PurePosixPath
-from typing import Optional, Iterable
 
 from ..translations import smart_gettext as _
 from .common_errors import *
@@ -49,9 +50,13 @@ class Piggybacked:
         'resource_must_depend' (read-only)
         'package_license_files' (read-only)
     """
-    def __init__(self, archives: dict[str, Path]={}, roots: dict[str, Path]={},
-                 package_license_files: list[PurePosixPath]=[],
-                 resource_must_depend: list[dict]=[]):
+    def __init__(
+            self,
+            archives:              dict[str, Path]     = {},
+            roots:                 dict[str, Path]     = {},
+            package_license_files: list[PurePosixPath] = [],
+            resource_must_depend:  list[dict]          = []
+    ) -> None:
         """
         Initialize this Piggybacked object.
 
@@ -77,7 +82,7 @@ class Piggybacked:
         self.package_license_files = package_license_files
         self.resource_must_depend  = resource_must_depend
 
-    def resolve_file(self, file_ref_name: PurePosixPath) -> Optional[Path]:
+    def resolve_file(self, file_ref_name: PurePosixPath) -> t.Optional[Path]:
         """
         'file_ref_name' is a path as may appear in an index.json file. Check if
         the file belongs to one of the roots we have and return either a path
@@ -107,7 +112,7 @@ class Piggybacked:
 
         return path
 
-    def archive_files(self) -> Iterable[tuple[PurePosixPath, Path]]:
+    def archive_files(self) -> t.Iterator[tuple[PurePosixPath, Path]]:
         """
         Yield all archive files in use. Each yielded tuple holds file's desired
         path relative to the piggybacked archives directory to be created and