class py_solution:  
   def is_valid_parenthese(self, str1):  
        stack, pchar = [], {"(": ")", "{": "}", "[": "]"}  
        for parenthese in str1:  
            if parenthese in pchar:  
                stack.append(parenthese)  
            elif len(stack) == 0 or pchar[stack.pop()] != parenthese:  
                return False  
        return len(stack) == 0  
  
print(py_solution().is_valid_parenthese("(){}[]"))  
print(py_solution().is_valid_parenthese("()[{)}"))  
print(py_solution().is_valid_parenthese("()"))