Python code modernization, 5/n (#1165)

* Address raise-missing-from.

* Address simplifiable-if-expression.

* Address unnecessary-dunder-call.

* Address unnecessary-pass.

* Address use-list-literal.

* Address unused-variable.

* Address use-dict-literal.

plugins/module_utils/_copy.py

@@ -285,7 +285,7 @@ def stat_file(client, container, in_path, follow_links=False, log=None):
         except Exception as exc:
             raise DockerUnexpectedError(
                 f"When retrieving information for {in_path} from {container}, obtained header {header!r} that cannot be loaded as JSON: {exc}"
-            )
+            ) from exc
 
         # https://pkg.go.dev/io/fs#FileMode: bit 32 - 5 means ModeSymlink
         if stat_data["mode"] & (1 << (32 - 5)) != 0:
@@ -500,7 +500,7 @@ def _execute_command(client, container, command, log=None, check_rc=False):
 
 
 def determine_user_group(client, container, log=None):
-    dummy, stdout, stderr = _execute_command(
+    dummy_rc, stdout, dummy_stderr = _execute_command(
         client, container, ["/bin/sh", "-c", "id -u && id -g"], check_rc=True, log=log
     )
 
@@ -513,7 +513,7 @@ def determine_user_group(client, container, log=None):
     user_id, group_id = stdout_lines
     try:
         return int(user_id), int(group_id)
-    except ValueError:
+    except ValueError as exc:
         raise DockerUnexpectedError(
             f'Expected two-line output with numeric IDs to obtain user and group ID for container {container}, but got "{user_id}" and "{group_id}" instead'
-        )
+        ) from exc