class PropSquare:
    def __init__(self, start):
        self.value = start

    def getX(self):                         # On attr fetch
        return self.value ** 2

    def setX(self, value):                  # On attr assign
        self.value = value

    X = property(getX, setX)                # No delete or docs

P = PropSquare(3)       # Two instances of class with property
Q = PropSquare(32)      # Each has different state information

print(P.X)              # 3 ** 2
P.X = 4
print(P.X)              # 4 ** 2
print(Q.X)              # 32 ** 2 (1024)