Update mychain.py

mychain.py

@@ -35,7 +35,7 @@ class Blockchain:
         if chain_n !="" and chain_n !=None:
             chain_n = f"{main_chain.split('main/',1)[1]}{chain_n}"
         if chain_n=="" or chain_n==None:
-            chain_n=chain_d
+            chain_n=f"{main_chain.split('main/',1)[1]}{chain_d}"
         block = {'index': len(self.chain) + 1,
                 'timestamp': str(datetime.datetime.now()),
                 'transactions': self.pending_transactions,