Write a python function to count the occurrence of a given character in a string.
def count(s,c) : 
    res = 0 
    for i in range(len(s)) : 
        if (s[i] == c): 
            res = res + 1
    return res 
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a python function to count the occurrence of a given character in a string.
def count(s,c) : 
    res = 0 
    for i in range(len(s)) : 
        if (s[i] == c): 
            res = res + 1
    return res [/INST]assert count("abcc","c") == 2
assert count("ababca","a") == 3
assert count("mnmm0pm","m") == 4</s>