fix crash when backtest-result.json not exist

freqtrade/arguments.py

@@ -352,9 +352,9 @@ class Arguments(object):
         Parses given arguments for scripts.
         """
         self.parser.add_argument(
-            '-p', '--pair',
+            '-p', '--pairs',
             help='Show profits for only this pairs. Pairs are comma-separated.',
-            dest='pair',
+            dest='pairs',
             default=None
         )
 

freqtrade/tests/test_arguments.py

@@ -47,7 +47,7 @@ def test_scripts_options() -> None:
     arguments = Arguments(['-p', 'ETH/BTC'], '')
     arguments.scripts_options()
     args = arguments.get_parsed_arg()
-    assert args.pair == 'ETH/BTC'
+    assert args.pairs == 'ETH/BTC'
 
 
 def test_parse_args_version() -> None: