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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 updated_dimensions(self):
 """ Inform montblanc about dimension sizes """

        return [("ntime", args.ntime),      # Timesteps
                ("nchan", args.nchan),      # Channels
                ("na", args.na),            # Antenna
                ("npsrc", len(lm_coords))]