170. Two Sum III - Data structure design

def __init__(self):
        """
        Initialize your data structure here.
        """
        self.d = {}

    def add(self, number):
        """
        Add the number to an internal data structure..
        :type number: int
        :rtype: void
        """
        self.d[number] = self.d.get(number, 0) + 1

    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 num in self.d:
            if value - num in self.d and (value - num != num or self.d[num] > 1):
                return True
        return False