Absorbtion is not invariant to order of args.

[tomas789]

The function absorb should produce the same results no matter the order of the args passed to it.

There is a counter-example where this property does not hold.

import boolean
        
algebra = boolean.BooleanAlgebra()
TRUE, FALSE, NOT, AND, OR, symbol = algebra.definition()

e = AND(OR(NOT(symbol("x1")), NOT(symbol("x2"))), TRUE, symbol("x2"), NOT(symbol("x1")))
args = [
    OR(NOT(symbol("x1")), NOT(symbol("x2"))),
    NOT(symbol("x1")),
    symbol("x2"),
]
print("ORIGINAL ORDER")
print(e.absorb(args))

args[1], args[2] = args[2], args[1]
print("SWAPPED")
print(e.absorb(args))

Which produces following output

ORIGINAL ORDER
[NOT(Symbol('x1')), Symbol('x2')]
SWAPPED
[NOT(Symbol('x1')), Symbol('x2'), NOT(Symbol('x1'))]

[tomas789]

After more investigation it looks like this is the core cause of the previous issue #111

[pombredanne]

Fixed with #113 Thank you ++