[Python] Extending sympy variable definition to binary

I am trying to extend the symbol class to a binary variable, where + would mimic an XOR operator such that

x + y -> x + y

x + x -> 0

I have referenced the this code here and added _eval_add but it doesn't seem to call the function.

This is my code:

from sympy import Symbol, Integer

class XorBinary(Symbol):

def _eval_power(self, other):
if other % 2 == 0:
return Integer(1)
elif self == other:
return Integer(0)
else:
return self

def _eval_add(self, other):
print("add", self, other)
if self == other:
return Integer(0)
return self

# Example usage
x = XorBinary("x")
y = XorBinary("y")

print("x^2 =", x**2) # -> 1
print("x^3 =", x**3) # -> x
print("x^0 =", x**0) # -> 1
print("x*x =", x*x) # -> x
print("x+x =", x + x) # -> x
print("x+y =", x+y) # normal sum (unless XOR enforced)

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