def xor_string_value(first_string, second_string):
    """
    Runs the xor bitwise operation over all the items
    of both strings, retrieving the result.

    :type first_string: String
    :param first_string: The first string to the xor operation.
    :type second_string: String
    :param second_string: The second string to the xor operation.
    :rtype: String
    :return: The "string" result of the xor operation.
    """
    first_string_length = len(first_string)
    second_string_length = len(second_string)
    if not first_string_length == second_string_length:
        raise ValueError('Arguments to xor string must have the same length')
    result_character_list = []
    for first_character, second_character in zip(first_string, second_string):
        result_character = chr(ord(first_character) ^ ord(second_character))
        result_character_list.append(result_character)
    xor_result = ''.join(result_character_list)
    return xor_result
