Else increment start Also checkin for X at start position
else : NEW_LINE INDENT if ( s [ start ] == X ) : NEW_LINE INDENT s [ start ] = Y ; NEW_LINE DEDENT start += 1 ; NEW_LINE DEDENT while ( len ( s ) > 0 and s [ len ( s ) - 1 ] == Z ) : NEW_LINE s . pop ( ) ; NEW_LINE return " " . join ( s ) NEW_LINE