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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 counter(group, counter, amount=1, err=None):
 """Output a counter update that is displayed in the Hadoop web interface Counters are useful for quickly identifying the number of times an error occurred, current progress, or coarse statistics. :param group: Counter group :param counter: Counter name :param amount: Value to add (default 1) :param err: Func that outputs a string, if None then sys.stderr.write is used (default None) """

    if not err:
        err = _err
    err("reporter:counter:%s,%s,%s\n" % (group, counter, str(amount)))