Update blockchain.py

blockchain.py

@@ -29,7 +29,7 @@ class Blockchain:
         if chain_r=="" or chain_r==None:
             chain_r=f"{main_chain.split('datasets/',1)[1].split('/raw',1)[0]}"
         if chain_n !="" and chain_n !=None:
-            chain_n = f'{main_chain.split('main/',1)[1]}{chain_n}'
+            chain_n = f"{main_chain.split('main/',1)[1]}{chain_n}"
         if chain_n=="" or chain_n==None:
             chain_n=chain_d
         block = {'index': len(self.chain) + 1,