typing: fix functools.partial call

Since mypy v1.11, uses of functools.partial are checked. Implementing
protocol, since I didnt find other way to handle a generic `sig_handler`
reference to callables of type `SignalHandlers`.

Author: pavdmyt

yaspin/core.py

@@ -28,11 +28,13 @@
     Generator,
     Iterator,
     Optional,
+    Protocol,
     Sequence,
     Type,
     TypeVar,
     Union,
     cast,
+    runtime_checkable,
 )
 
 from termcolor import ATTRIBUTES, COLORS, HIGHLIGHTS, colored
@@ -64,6 +66,11 @@ class Spinner:
 default_spinner = Spinner("⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏", 80)
 
 
+@runtime_checkable
+class SignalHandlerProtocol(Protocol):
+    def __call__(self, signum: int, frame: Any, spinner: Yaspin) -> None: ...
+
+
 def default_handler(signum: int, frame: Any, spinner: Yaspin) -> None:  # pylint: disable=unused-argument
     """Signal handler, used to gracefully shut down the ``spinner`` instance
     when specified signal is received by the process running the ``spinner``.
@@ -506,7 +513,7 @@ def _register_signal_handlers(self) -> None:
 
             # ``signal.SIG_DFL`` and ``signal.SIG_IGN`` are also valid
             # signal handlers and are not callables.
-            if callable(sig_handler):
+            if callable(sig_handler) and isinstance(sig_handler, SignalHandlerProtocol):
                 # ``signal.signal`` accepts handler function which is
                 # called with two arguments: signal number and the
                 # interrupted stack frame. ``functools.partial`` solves