def separator(s):
    """
    From any string, return the list composed of each character that are in the string
    :param s: String to be separated character by character like '121211'
    :return: Separated list of characters where one can look like ['1', '2', '1', '2', '1', '1']
    """
    result = []
    for i in s:
        result.append(i)
    return result