diff --git a/samplelib/SampleGeneratorFacePerson.py b/samplelib/SampleGeneratorFacePerson.py
index c5d53e9..f0a927f 100644
--- a/samplelib/SampleGeneratorFacePerson.py
+++ b/samplelib/SampleGeneratorFacePerson.py
@@ -37,19 +37,14 @@ class SampleGeneratorFacePerson(SampleGeneratorBase):
 
         if self.samples_len == 0:
             raise ValueError('No training data provided.')
-        
-        persons_name_idxs = {}
-        
-        for i,sample in enumerate(samples):
-            person_name = sample.person_name
-            if person_name not in persons_name_idxs:
-                persons_name_idxs[person_name] = []                
-            persons_name_idxs[person_name].append (i)
-  
-        indexes2D = [ persons_name_idxs[person_name] for person_name in sorted(list(persons_name_idxs.keys())) ]
+
+        unique_person_names = { sample.person_name for sample in samples } 
+        persons_name_idxs = { person_name : [] for person_name in unique_person_names }        
+        for i,sample in enumerate(samples):            
+            persons_name_idxs[sample.person_name].append (i)  
+        indexes2D = [ persons_name_idxs[person_name] for person_name in unique_person_names ]
         index2d_host = mp_utils.Index2DHost(indexes2D)
         
-
         if self.debug:
             self.generators_count = 1
             self.generators = [iter_utils.ThisThreadGenerator ( self.batch_func, (samples_host.create_cli(), index2d_host.create_cli(),) )]