Remove a hook.

        :param addr:    The address of the hook.

def unhook(self, addr):
        """
        Remove a hook.

        :param addr:    The address of the hook.
        """
        if not self.is_hooked(addr):
            l.warning("Address %s not hooked", self._addr_to_str(addr))
            return

        del self._sim_procedures[addr]