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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 escape(s, fold_newlines=True):
 """Escapes a string to make it usable in LaTeX text mode. Will replace special characters as well as newlines. Some problematic characters like ``[`` and ``]`` are escaped into groups (e.g. ``{[}``), because they tend to cause problems when mixed with ``\\`` newlines otherwise. :param s: The string to escape. :param fold_newlines: If true, multiple newlines will be reduced to just a single ``\\``. Otherwise, whitespace is kept intact by adding multiple ``[n\baselineskip]``. """


    def sub(m):
        c = m.group()
        if c in CHAR_ESCAPE:
            return CHAR_ESCAPE[c]

        if c.isspace():
            if fold_newlines:
                return r'\\'
            return r'\\[{}\baselineskip]'.format(len(c))

    return ESCAPE_RE.sub(sub, s)