Pretty old thread, but I was having the same issue and have solved it. Here is what you need to do:
 new=list(pre_trained.items())

my_model_kvpair=my_model.state_dict()
count=0
for key,value in my_model_kvpair.item():
  layer_name,weights=new[count]      
  mymodel_kvpair[key]=weights
  count+=1

my_model.load_state_dict(my_model_kv_pair)

After modifying the key value pairs, you need to actually load the updated state_dict back into your model so that the weights and biases change