add json flag to cast commands

parse.py

@@ -427,13 +427,15 @@ def voucher_transfer_handler(cmd):
     f'--rpc-url {rpc} '
     f'{s} '
     f'"transfer(address,uint256)" {to} {value}'
+    f' --json '
    )
    result = subprocess.run(command, shell=True, capture_output=True, text=True)
    if result.returncode != 0:
         raise subprocess.CalledProcessError(result.returncode, command, output=result.stdout, stderr=result.stderr)
    if result.stderr:
         raise ValueError(f"Command failed with error: {result.stderr}")
-   return result.stdout
+   data = json.loads(result.stdout)
+   return data["transactionHash"]
    
 
     
@@ -468,13 +470,15 @@ def voucher_mint_handler(cmd):
         f'--rpc-url {rpc} '
         f' {s} '
         f'"mintTo(address,uint256)" {to} {value}'
+        f' --json '
     )
     result = subprocess.run(command, shell=True, capture_output=True, text=True)
     if result.returncode != 0:
         raise subprocess.CalledProcessError(result.returncode, command, output=result.stdout, stderr=result.stderr)
     if result.stderr:
         raise ValueError(f"Command failed with error: {result.stderr}")
-    return result.stdout
+    data = json.loads(result.stdout)
+    return data["transactionHash"]