[fix] Fix inverted error message

Author: slarse

repobee_feedback/feedback.py

@@ -24,9 +24,7 @@
 
 
 def callback(args: argparse.Namespace, api: plug.API) -> None:
-    repo_names = plug.generate_repo_names(
-        args.students, args.master_repo_names
-    )
+    repo_names = plug.generate_repo_names(args.students, args.master_repo_names)
     if "multi_issues_file" in args and args.multi_issues_file is not None:
         issues_file = pathlib.Path(args.multi_issues_file).resolve()
         all_issues = _parse_multi_issues_file(issues_file)
@@ -123,9 +121,7 @@ def _ask_for_open(issue: plug.Issue, repo_name: str, trunc_len: int) -> bool:
         )
     )
     return (
-        input(
-            'Open issue "{}" in repo {}? (y/n) '.format(issue.title, repo_name)
-        )
+        input('Open issue "{}" in repo {}? (y/n) '.format(issue.title, repo_name))
         == "y"
     )
 
@@ -143,9 +139,7 @@ def _extract_expected_issues(
         (repo_name for repo_name, _ in expected_repos_and_issues)
     )
     if missing_repos:
-        raise plug.PlugError(
-            "Missing issues for: " + ", ".join(expected_repo_names)
-        )
+        raise plug.PlugError("Missing issues for: " + ", ".join(missing_repos))
 
     return expected_repos_and_issues
 
@@ -170,15 +164,11 @@ def _read_issue(issue_path: pathlib.Path) -> plug.Issue:
 def _parse_multi_issues_file(
     issues_file: pathlib.Path
 ) -> Iterable[Tuple[str, plug.Issue]]:
-    with open(
-        str(issues_file), mode="r", encoding=sys.getdefaultencoding()
-    ) as file:
+    with open(str(issues_file), mode="r", encoding=sys.getdefaultencoding()) as file:
         lines = list(file.readlines())
 
     if not lines or not re.match(BEGIN_ISSUE_PATTERN, lines[0], re.IGNORECASE):
-        raise plug.PlugError(
-            "first line of multi issues file not #ISSUE# line"
-        )
+        raise plug.PlugError("first line of multi issues file not #ISSUE# line")
 
     issue_blocks = _extract_issue_blocks(lines)
     return list(_extract_issues(issue_blocks, lines))