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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_host_line(line):
 """ Processes a line and determines whether it is a tab-delimited CSV of url and host. Strips all strings. @param line: the line to analyse. @param opts: the options dictionary to modify. @return: a tuple containing url, and host header if any change is required. Otherwise, line, null is returned. """

    if not line:
        return None, None

    host = None
    if _line_contains_host(line):
        url, host = re.split(SPLIT_PATTERN, line.strip())
    else:
        url = line.strip()

    return url, host