def find(self, value):
        """
        Find if there exists any pair of numbers which sum is equal to the value.
        :type value: int
        :rtype: bool
        """
        for v in self.internal:
            if value - v in self.dic:
                if v << 1 == value and not self.dic[v]:
                    continue
                return True
        return False

        Find if there exists any pair of numbers which sum is equal to the value.
        :type value: int
        :rtype: bool
        
python/170_Two_Sum_III-Data_structure_design.py