def _non_string_elements(x):
    """
    Simple helper to check that all values of x are string. Returns all non string elements as (position, element).
    :param x: Iterable
    :return: [(int, !String), ...]
    """

    problems = []
    for i in range(0, len(x)):
        if not isinstance(x[i], str):
            problems.append((i, x[i]))
    return problems