if the characters contained in the two sets are same , return true
if ( diff [ 0 ] [ 0 ] == diff [ 1 ] [ 0 ] and diff [ 0 ] [ 1 ] == diff [ 1 ] [ 1 ] ) or ( diff [ 0 ] [ 0 ] == diff [ 1 ] [ 1 ] and diff [ 0 ] [ 1 ] == diff [ 1 ] [ 0 ] ) : NEW_LINE INDENT return True NEW_LINE DEDENT return False NEW_LINE