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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 _fmt_metric(value, show_stdv=True):
 """format metric string"""

    if len(value) == 2:
        return '%s:%g' % (value[0], value[1])
    if len(value) == 3:
        if show_stdv:
            return '%s:%g+%g' % (value[0], value[1], value[2])
        return '%s:%g' % (value[0], value[1])
    raise ValueError("wrong metric value")