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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 _mark_quoted_email_splitlines(markers, lines):
 """ When there are headers indented with '>' characters, this method will attempt to identify if the header is a splitline header. If it is, then we mark it with 's' instead of leaving it as 'm' and return the new markers. """

    # Create a list of markers to easily alter specific characters
    markerlist = list(markers)
    for i, line in enumerate(lines):
        if markerlist[i] != 'm':
            continue
        for pattern in SPLITTER_PATTERNS:
            matcher = re.search(pattern, line)
            if matcher:
                markerlist[i] = 's'
                break

    return "".join(markerlist)