Write a python function to find the first repeated character in a given string.
def first_Repeated_Char(str): 
    h = {}
    for ch in str:
        if ch in h: 
            return ch;
        else: 
            h[ch] = 0
    return '\0'
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a python function to find the first repeated character in a given string.
def first_Repeated_Char(str): 
    h = {}
    for ch in str:
        if ch in h: 
            return ch;
        else: 
            h[ch] = 0
    return '\0'[/INST]assert first_Repeated_Char("Google") == "o"
assert first_Repeated_Char("data") == "a"
assert first_Repeated_Char("python") == '\0'</s>