Is there an unmatched parenthesis in this String?
Python 2, 47 bytes



lambda s:map(s.count,'([{')!=map(s.count,')]}')


Try it online! Test cases from musicman523.

Checks if list of counts for each type of open paren matches that for the corresponding close parens.

The program is one byte longer

q=input().count
print map(q,'([{')!=map(q,')]}')