<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def normalize(self):
 """ Return a new time series with all values normalized to 0 to 1. :return: `None` """

        maximum = self.max()
        if maximum:
            self.values = [value / maximum for value in self.values]