delete type hints

pyxtal_ff/models/neuralnetwork.py

@@ -512,7 +512,7 @@ def mutli_thread_loss(self, model, batch):
         return output
 
     @staticmethod
-    def _sum_together(output: list[list[float]]) -> list[float]:
+    def _sum_together(output):
         res = [0 for _ in range(len(output[0]))]
         for cur in output:
             res = [i+j for (i, j) in zip(res, cur)]
@@ -1051,13 +1051,15 @@ def normalize(self, data, drange, unit, norm=[0., 1.]):
 
     def get_stress_group(self, data):
         """ Get every kind of stress groups if None is defined by the user. """
+        print("self.stress_group is ", self.stress_group)
         if self.stress_coefficient and (self.stress_group is None):
             db = shelve.open(self.path+data)
             sg = []
             for i in range(self.no_of_structures):
                 if db[str(i)]['group'] not in sg:
                     sg.append(db[str(i)]['group'])
             self.stress_group = sg
+        print("self.stress_group is ", self.stress_group)
 
 
     def _SOFTMAX(self, data, beta=-1):