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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 _is_master_running(self):
        '''
        Perform a lightweight check to see if the master daemon is running

        Note, this will return an invalid success if the master crashed or was
        not shut down cleanly.
        '''
        # Windows doesn't have IPC. Assume the master is running.
        # At worse, it will error 500.
        if salt.utils.platform.is_windows():
            return True

        if self.opts['transport'] == 'tcp':
            ipc_file = 'publish_pull.ipc'
        else:
            ipc_file = 'workers.ipc'
        return os.path.exists(os.path.join(
            self.opts['sock_dir'],
            ipc_file))