In this kata, we want to discover a small property of numbers. 
We say that a number is a **dd** number if it contains d occurences of a digit d, (d is in [1,9]).
## Examples
* 664444309 is a **dd** number, as it contains 4 occurences of the number 4
* 30313, 122 are **dd** numbers as they respectively contain 3 occurences of the number 3, and (1 occurence of the number 1 AND 2 occurences of the number 2)
* 123109, 0, 56542 are not **dd** numbers
## Task 
Your task is to implement a function called `is_dd` (`isDd` in javascript) that takes a **positive** number (type depends on the language) and returns a boolean corresponding to whether the number is a **dd** number or not.
from collections import Counter


def is_dd(n):
    return any(value==count for value, count in Counter(int(x) for x in str(n)).items())
from collections import Counter


def is_dd(n):
    return any(value==count for value, count in Counter(int(x) for x in str(n)).items())