Added a missing comma

uuv_plume_simulator/src/uuv_gm_process/gauss_markov_process.py

@@ -57,7 +57,7 @@ def set_model(self, mean, min_value, max_value, mu, noise_amp):
         assert min_value < max_value, 'Min. value must be smaller than max. value'
         assert min_value < mean < max_value, 'Mean value must be in the interval delimited by min. and max. value'
         assert mu >= 0, 'Mu must be greater or equal to zero'
-        assert noise_amp >= 0 'Noise amplitude must be greater or equal to zero'
+        assert noise_amp >= 0, 'Noise amplitude must be greater or equal to zero'
 
         self._mean = mean
         self._min = min_value