[api-change] Remove Backend.characterisation (#226)

pytket/docs/changelog.rst

@@ -11,6 +11,8 @@ API changes:
 * The deprecated ``Backend.compile_circuit`` method is removed. (Use
   ``get_compiled_circuit`` instead.)
 * ``RebaseCustom`` takes one allowed gateset parameter rather than separate single qubit and multiqubit gatesets.
+* The ``Backend.characterisation`` property is removed. (Use
+  ``Backend.backend_info`` instead.)
 
 Minor new features:
 

pytket/pytket/backends/backend.py

@@ -406,19 +406,6 @@ def cancel(self, handle: ResultHandle) -> None:
         """
         raise NotImplementedError("Backend does not support job cancellation.")
 
-    @property
-    def characterisation(self) -> Optional[dict]:
-        """Retrieve the characterisation targeted by the backend if it exists.
-
-        :return: The characterisation that this backend targets if it exists. The
-            characterisation object contains device-specific information such as gate
-            error rates.
-        :rtype: Optional[dict]
-        """
-        raise NotImplementedError(
-            "Backend does not support retrieving characterisation."
-        )
-
     @property
     def backend_info(self) -> Optional[BackendInfo]:
         """Retrieve all Backend properties in a BackendInfo object, including