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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 AddStationDecoration(self, index, color="#f00"):
 """Flushes existing decorations and highlights the given station-line. Args: # Integer, index of stop to be highlighted. index: 4 # An optional string with a html color code color: "#fff" """

    tmpstr = str()
    num_stations = len(self._stations)
    ind = int(index)
    if self._stations:
      if 0<ind<num_stations:
        y = self._stations[ind]
        tmpstr = '<polyline class="Dec" stroke="%s" points="%s,%s,%s,%s" />' \
          % (color, 20, 20+y+.5, self._gwidth+20, 20+y+.5)
    self._decorators.append(tmpstr)