stronger validators

kvmd/validators/__init__.py

@@ -26,6 +26,7 @@ from typing import List
 from typing import Mapping
 from typing import Sequence
 from typing import Callable
+from typing import TypeVar
 from typing import NoReturn
 from typing import Union
 from typing import Any
@@ -36,6 +37,10 @@ class ValidatorError(ValueError):
     pass
 
 
+# =====
+_RetvalSeqT = TypeVar("_RetvalSeqT", bound=Sequence)
+
+
 # =====
 def raise_error(arg: Any, name: str, hide: bool=False) -> NoReturn:
     arg_str = " "
@@ -77,6 +82,12 @@ def check_re_match(arg: Any, name: str, pattern: str, strip: bool=True, hide: bo
     return arg
 
 
+def check_len(arg: _RetvalSeqT, name: str, limit: int) -> _RetvalSeqT:
+    if len(arg) > limit:
+        raise_error(arg, name)
+    return arg
+
+
 def check_any(arg: Any, name: str, validators: List[Callable[[Any], Any]]) -> Any:
     for validator in validators:
         try: