diff --git a/src/local_ops.py b/src/local_ops.py
index a55270b..499eb6d 100644
--- a/src/local_ops.py
+++ b/src/local_ops.py
@@ -568,10 +568,11 @@ def remove_file(self, filename):
         return os.remove(filename)
 
     # Processes control
-    def kill(self, pid, signal, expect_error=False):
+    def kill(self, pid: int, signal: int):
         # Kill the process
-        cmd = "kill -{} {}".format(signal, pid)
-        return self.exec_command(cmd, expect_error=expect_error)
+        assert type(pid) == int  # noqa: E721
+        assert type(signal) == int  # noqa: E721
+        os.kill(pid, signal)
 
     def get_pid(self):
         # Get current process id
diff --git a/src/os_ops.py b/src/os_ops.py
index 4642226..f43f8c7 100644
--- a/src/os_ops.py
+++ b/src/os_ops.py
@@ -126,8 +126,10 @@ def remove_file(self, filename):
         raise NotImplementedError()
 
     # Processes control
-    def kill(self, pid, signal):
+    def kill(self, pid: int, signal: int):
         # Kill the process
+        assert type(pid) == int  # noqa: E721
+        assert type(signal) == int  # noqa: E721
         raise NotImplementedError()
 
     def get_pid(self):
diff --git a/src/remote_ops.py b/src/remote_ops.py
index 7fcc642..42eede9 100644
--- a/src/remote_ops.py
+++ b/src/remote_ops.py
@@ -658,8 +658,10 @@ def remove_file(self, filename):
         return self.exec_command(cmd)
 
     # Processes control
-    def kill(self, pid, signal):
+    def kill(self, pid: int, signal: int):
         # Kill the process
+        assert type(pid) == int  # noqa: E721
+        assert type(signal) == int  # noqa: E721
         cmd = "kill -{} {}".format(signal, pid)
         return self.exec_command(cmd)