def xor_fault(a, b, out, fault):
if (a != b) == out:<EOL><INDENT>return fault == <NUM_LIT:0><EOL><DEDENT>else:<EOL><INDENT>return fault == <NUM_LIT:1><EOL><DEDENT>
Returns True if XOR(a, b) == out and fault == 0 or XOR(a, b) != out and fault == 1.