Update mychain.py

mychain.py

@@ -197,6 +197,7 @@ class MyChainSend:
             json_object = json.dumps(self.chain, indent=4)
             with open("tmp_send.json", "w") as outfile:
                 outfile.write(json_object)
+            outfile.close()
             try: 
                 api.upload_file(
                 path_or_fileobj="tmp_send.json",
@@ -389,6 +390,7 @@ class MyChainRec:
             json_object = json.dumps(self.chain, indent=4)
             with open("tmp_rec.json", "w") as outfile:
                 outfile.write(json_object)
+            outfile.close()
             try: 
                 api.upload_file(
                 path_or_fileobj="tmp_rec.json",
@@ -532,6 +534,7 @@ class MyChainTrans:
             json_object = json.dumps(self.chain, indent=4)
             with open("tmp_trans.json", "w") as outfile:
                 outfile.write(json_object)
+            outfile.close()
             try: 
                 api.upload_file(
                 path_or_fileobj="tmp_trans.json",