# define another custom function
def interested_user_count(user_list, topic):
    """
        Function to count number of users interested in an arbitrary topic
    """
    count = 0

    for user in user_list:
        if topic in user["Interests"]:
            count = count + 1

    return count

# define user list and topic
user_list = [user_dict, new_user_dict]
topic = "Shopping"

# compute interested user count and print it
count = interested_user_count(user_list, topic)
print(f"{count} user(s) interested in {topic}")