def remove_dup_loop(input_list):
    """
    Remove all duplicates in list. Using loop method.
    
    Arguments:
    input_list -- a list input
    
    Returns:
    new_list -- a list remove all the duplicates.
    """
    new_list = []
    new_list.extend(i for i in input_list if i not in new_list)
    return new_list