doufo.Maybe.bind  
        Args:  
            `self`:  
            f (`Callable[[T], Maybe[B]`): A function that returns `Maybe[B]`  
        Returns:  
            return (`Maybe[B]`): results of mapping in form of `Maybe[B]`  
        Raises:

def bind(self, f: Callable[[T], 'Maybe[B]']) -> 'Maybe[B]':
        """doufo.Maybe.bind  
        Args:  
            `self`:  
            f (`Callable[[T], Maybe[B]`): A function that returns `Maybe[B]`  
        Returns:  
            return (`Maybe[B]`): results of mapping in form of `Maybe[B]`  
        Raises:
        """
        return self.fmap(lambda x: f(x).unbox())