Gracefully handle missing fields for the trade balance summary

Author: zertrin

src/clikraken/api/private/get_trade_balance.py

@@ -22,14 +22,14 @@ def get_trade_balance(args=None):
     res = query_api('private', 'TradeBalance', api_params, args)
 
     tbal_list = [
-        ['equivalent balance', res['eb']],
-        ['trade balance', res['tb']],
-        ['margin amount of open positions', res['m']],
-        ['cost basis of open positions', res['c']],
-        ['current floating valuation of open positions', res['v']],
-        ['equity', res['e']],
-        ['free margin', res['mf']],
-        ['margin level', res['ml']],
-        ['unrealized net profit/loss of open positions', res['n']],
+        ['equivalent balance', res.get('eb', 'n/a')],
+        ['trade balance', res.get('tb', 'n/a')],
+        ['margin amount of open positions', res.get('m', 'n/a')],
+        ['cost basis of open positions', res.get('c', 'n/a')],
+        ['current floating valuation of open positions', res.get('v', 'n/a')],
+        ['equity', res.get('e', 'n/a')],
+        ['free margin', res.get('mf', 'n/a')],
+        ['margin level', res.get('ml', 'n/a')],
+        ['unrealized net profit/loss of open positions', res.get('n', 'n/a')],
     ]
     print(tabulate(tbal_list))