check if the string phone start with string start and print the result hackerrank code example

Example: find a string hackereank

def count_substring(string, sub_string):
    count=0  #initialise count variable
    for i in range(0,len(string)):
        if string[i:].startswith(sub_string): # basically it traverses from left to right and looks for occurence of substring
            count+=1 #every time count will increase by 1

    return count