remove an unused list in postprocess (#1002)

Co-authored-by: fatih cagatay akyon <[email protected]>

sahi/postprocess/combine.py

@@ -217,19 +217,12 @@ def greedy_nmm(
     # according to their confidence scores
     order = scores.argsort()
 
-    # initialise an empty list for
-    # filtered prediction boxes
-    keep = []
-
     while len(order) > 0:
         # extract the index of the
         # prediction with highest score
         # we call this prediction S
         idx = order[-1]
 
-        # push S in filtered predictions list
-        keep.append(idx.tolist())
-
         # remove S from P
         order = order[:-1]