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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 check_channel_shell_request(self, channel):
        '''Request to start a shell on the given channel'''
        try:
            self.channels[channel].start()
        except KeyError:
            log.error('Requested to start a channel (%r) that was not previously set up.', channel)
            return False
        else:
            return True