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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 trunc_str(s: str) -> str: """Truncate strings to maximum length."""

    if len(s) > max_str_size:
        i = max(0, (max_str_size - 3) // 2)
        j = max(0, max_str_size - 3 - i)
        s = s[:i] + "..." + s[-j:]
    return s