# Learn Special Methods by Building a Vector Space - Step 42

### Tell us what’s happening:

Sorry me again:
here we have two operands: self and other, right??
I do not know how to create the sum of the ‘i’ attribute of ‘self’ and the ‘i’ attribute of ‘other’
Can you give me some inputs? Grazie

``````class R2Vector:
def __init__(self, *, x, y):
self.x = x
self.y = y

def norm(self):
return sum(val**2 for val in vars(self).values())**0.5

def __str__(self):
return str(tuple(getattr(self, i) for i in vars(self)))

def __repr__(self):
arg_list = [f'{key}={val}' for key, val in vars(self).items()]
args = ', '.join(arg_list)
return f'{self.__class__.__name__}({args})'

# User Editable Region

if type(self) != type(other):
return NotImplemented
kwargs = {i: getattr(self, i) for i in vars(self)}

# User Editable Region

class R3Vector(R2Vector):
def __init__(self, *, x, y, z):
super().__init__(x=x, y=y)
self.z = z

v1 = R2Vector(x=2, y=3)
v2 = R3Vector(x=2, y=2, z=3)
print(f'v1 = {v1}')
print(f'v2 = {v2}')
``````

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### Challenge Information:

Learn Special Methods by Building a Vector Space - Step 42

Hello,
your code is almost correct, you have to add `getattr(other, i)` to `getattr(self, i)` to make it work
remember that the `other` variable represents another instance of the `R2Vector` class

1 Like

but you deleted getattr so how??