Find a String Hackerrank

Input:ABCDCDC
CDC
Output:2

def count_substring(string, sub_string):
        for i in range(0,len(string)):
            ans=string.count(sub_string)
            return ans

I am getting 1 as output how can I get 2 as output and read the full string

>Solution :

From every index look forward for next n characters if they match, n being the size of substring

def count_substring(string, sub_string):
    n = len(sub_string)
    ans = 0
    for i in range(0,len(string)):
        if(i+n > len(string)):#out of range problem
            break
        ans+=string.count(sub_string,i,i+n)
    return ans