default token

cantok/errors.py

@@ -13,3 +13,6 @@ class CounterCancellationError(CancellationError):
 
 class TimeoutCancellationError(CancellationError):
     pass
+
+class impossibleException(CancellationError):
+    pass

cantok/tokens/default_token.py

@@ -0,0 +1,33 @@
+from cantok import AbstractToken
+from cantok.errors import impossibleException
+
+
+class DefaultToken(AbstractToken):
+    exception = impossibleException
+
+    def __init__(self):
+        super().__init__()
+
+    def superpower(self) -> bool:
+        return False
+
+    def text_representation_of_superpower(self) -> str:
+        return ''
+
+    def get_superpower_exception_message(self) -> str:
+        return 'This exception should not be raised.'  # pragma: no cover
+
+    @property
+    def cancelled(self) -> bool:
+        return False
+
+    @cancelled.setter
+    def cancelled(self, new_value: bool) -> None:
+        if new_value == True:
+            raise ValueError('You cannot cancel a default token.')
+
+    def keep_on(self) -> bool:
+        return True
+
+    def is_cancelled(self, direct: bool = True) -> bool:
+        return False