How to use the pyedflib.edfwriter.ChannelDoesNotExist function in pyEDFlib

"""
        Sets the parameter for signal edfsignal.

        channel_info should be a dict with
        these values:

            'label' : channel label (string, <= 16 characters, must be unique)
            'dimension' : physical dimension (e.g., mV) (string, <= 8 characters)
            'sample_rate' : sample frequency in hertz (int)
            'physical_max' : maximum physical value (float)
            'physical_min' : minimum physical value (float)
            'digital_max' : maximum digital value (int, -2**15 <= x < 2**15)
            'digital_min' : minimum digital value (int, -2**15 <= x < 2**15)
        """
        if edfsignal < 0 or edfsignal > self.n_channels:
            raise ChannelDoesNotExist(edfsignal)
        self.channels[edfsignal] = channel_info
        self.update_header()

def setPhysicalDimension(self, edfsignal, physical_dimension):
        """
        Sets the physical dimension of signal edfsignal ("uV", "BPM", "mA", "Degr.", etc.)

        :param edfsignal: int
        :param physical_dimension: str

        Notes
        -----
        This function is recommended for every signal 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]['dimension'] = physical_dimension
        self.update_header()

"""
        Sets the label (name) of signal edfsignal ("FP1", "SaO2", etc.).

        Parameters
        ----------
        edfsignal : int
            signal number on which the label should be changed
        label : str
            signal label

        Notes
        -----
        This function is recommended for every signal 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]['label'] = label
        self.update_header()

def setSamplefrequency(self, edfsignal, samplefrequency):
        """
        Sets the samplefrequency of signal edfsignal.

        Notes
        -----
        This function is required for every signal 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]['sample_rate'] = samplefrequency
        self.update_header()

def setPrefilter(self, edfsignal, prefilter):
        """
        Sets the prefilter of signal edfsignal ("HP:0.1Hz", "LP:75Hz N:50Hz", etc.)

        :param edfsignal: int
        :param prefilter: str

        Notes
        -----
        This function is optional for every signal 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]['prefilter'] = prefilter
        self.update_header()

"""
        Sets the physical_maximum of signal edfsignal.

        Parameters
        ----------
        edfsignal: int
            signal number
        physical_maximum: float
            Sets the physical maximum

        Notes
        -----
        This function is required for every signal 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]['physical_max'] = physical_maximum
        self.update_header()

def setTransducer(self, edfsignal, transducer):
        """
        Sets the transducer of signal edfsignal

        :param edfsignal: int
        :param transducer: str

        Notes
        -----
        This function is optional for every signal 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]['transducer'] = transducer
        self.update_header()

Sets the minimum digital value of signal edfsignal.
        Usually, the value -32768 is used for EDF+ and -8388608 for BDF+. Usually this will be (-(digital_maximum + 1)).

        Parameters
        ----------
        edfsignal : int
            signal number
        digital_minimum : int
            Sets the minimum 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_min'] = digital_minimum
        self.update_header()

"""
        Sets the physical_minimum of signal edfsignal.

        Parameters
        ----------
        edfsignal: int
            signal number
        physical_minimum: float
            Sets the physical minimum

        Notes
        -----
        This function is required for every signal 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]['physical_min'] = physical_minimum
        self.update_header()

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()