Getting "'string' does not name a type" Error

Hello,

I am a beginner. Just to know the below details:

As per the above Sketch I posted earlier, I called the below function to get only RMC and GGA format...

GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA);

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But I am getting all the other formats also like below;

$GPRMC,,
$GPVTG,,,,,,,,,
$GPRMC,,
$GPVTG,,
$GPGGA,,
$GPGSV,
$GPGLL,

Can anyone suggest and provide help please..

Thanks-
Pokhraj