get_supported_bands
Description:
Gets the list of radio frequency and technology bands supported by the Modem.
For POTS devices, only ANY will be returned in bands.
Parameters:
| this | A Modem. | 
| bands | Return location for the array of ModemBand values. The returned array should be freed with g_free when no longer needed. | 
| n_bands | Return location for the number of values in  | 
Returns:
| 
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