Update blockchain.py

blockchain.py

@@ -28,6 +28,8 @@ class Blockchain:
     def create_block(self, proof, previous_hash,chain_r=None,chain_n=None):
         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 = main_chain.split('main/',1)[1]
         if chain_n=="" or chain_n==None:
             chain_n=chain_d
         block = {'index': len(self.chain) + 1,