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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 get_ylabel(self):
 """Text for y-axis label, check if channel defines it """

        units = self.units
        if len(units) == 1 and str(units[0]) == '':  # dimensionless
            return ''
        if len(units) == 1 and self.usetex:
            return units[0].to_string('latex')
        elif len(units) == 1:
            return units[0].to_string()
        elif len(units) > 1:
            return 'Multiple units'
        return super(TimeSeries, self).get_ylabel()