Return the function id of the given signature
    Args:
        sig (str)
    Return:
        (int)

def get_function_id(sig):
    ''''
        Return the function id of the given signature
    Args:
        sig (str)
    Return:
        (int)
    '''
    s = sha3.keccak_256()
    s.update(sig.encode('utf-8'))
    return int("0x" + s.hexdigest()[:8], 16)