Checking whether the constant added after all layers is even or odd .
if ( beven ) : NEW_LINE INDENT if ( b & 1 ) : NEW_LINE INDENT beven = False NEW_LINE DEDENT DEDENT elif ( not ( a & 1 ) ) : NEW_LINE INDENT if ( not ( b & 1 ) ) : NEW_LINE INDENT beven = True NEW_LINE DEDENT DEDENT else : NEW_LINE INDENT if ( b & 1 ) : NEW_LINE INDENT beven = True NEW_LINE DEDENT DEDENT