Duplicate values

[AugustinMortier]

There are duplicate values in GAWTADSulphurSubset/data/monthly_so4_aero.csv
eg: K-puszta, 2012-06
How should pyaerocom deal with it?

[jgriesfeller]

in the old aerocom-tools I did the following:
if we expect this to be a one time problem: modify the data file (e.g. in EBAS I sometimes had to remove a file), if we expect this to occur more often: foresee this in the code.

[hannasv]

For now, this is fixed in the reading routine (read_file method).