>>> from expressions import well_parenthesized_2

>>> well_parenthesized_2('((x+2)*(3*r/z))')
'correct'
>>> well_parenthesized_2('(f(x)))(5*x-y)')
('incorrect closed parenthesis', 6)
>>> well_parenthesized_2('((x+2)*(3*r/z)))')
('incorrect closed parenthesis', 15)
>>> well_parenthesized_2('((x+2)*(((3*r/z))')
'more open than closed parenthesis'