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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def process_sequence(sequence, rules=None, skip_non_vietnamese=True):
 """\ Convert a key sequence into a Vietnamese string with diacritical marks. Args: rules (optional):
 see docstring for process_key(). skip_non_vietnamese (optional):
 see docstring for process_key(). It even supports continous key sequences connected by separators. i.e. process_sequence('con meof.ddieen') should work. """

    result = ""
    raw = result
    result_parts = []
    if rules is None:
        rules = get_telex_definition()

    accepted_chars = _accepted_chars(rules)

    for key in sequence:
        if key not in accepted_chars:
            result_parts.append(result)
            result_parts.append(key)
            result = ""
            raw = ""
        else:
            result, raw = process_key(
                string=result,
                key=key,
                fallback_sequence=raw,
                rules=rules,
                skip_non_vietnamese=skip_non_vietnamese)

    result_parts.append(result)
    return ''.join(result_parts)