def cancel(self):
if self.cancelled:<EOL><INDENT>raise error.AlreadyCancelled<EOL><DEDENT>elif self.called:<EOL><INDENT>raise error.AlreadyCalled<EOL><DEDENT>else:<EOL><INDENT>self.canceller(self)<EOL>self.cancelled = <NUM_LIT:1><EOL>if self.debug:<EOL><INDENT>self._str = str(self)<EOL><DEDENT>del self.func, self.args, self.kw<EOL><DEDENT>
Unschedule this call

        @raise AlreadyCancelled: Raised if this call has already been
        unscheduled.

        @raise AlreadyCalled: Raised if this call has already been made.