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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 setDigitalMaximum(self, edfsignal, digital_maximum):
 """ Sets the samplefrequency of signal edfsignal. Usually, the value 32767 is used for EDF+ and 8388607 for BDF+. Parameters edfsignal : int signal number digital_maximum : int Sets the maximum digital value Notes ----- This function is optional and can be called only after opening a file in writemode and before the first sample write action. """

        if (edfsignal < 0 or edfsignal > self.n_channels):
            raise ChannelDoesNotExist(edfsignal)
        self.channels[edfsignal]['digital_max'] = digital_maximum
        self.update_header()