Replace filter usage

freqtrade/rpc/telegram.py

@@ -217,7 +217,8 @@ class Telegram(RPC):
 
                     "*Open Order:* `{open_order}`" if r['open_order'] else ""
                 ]
-                messages.append("\n".join(filter(None, lines)).format(**r))
+                # Filter empty lines using list-comprehension
+                messages.append("\n".join([l for l in lines if l]).format(**r))
 
             for msg in messages:
                 self._send_msg(msg, bot=bot)

freqtrade/tests/test_plotting.py

@@ -23,7 +23,7 @@ def fig_generating_mock(fig, *args, **kwargs):
 
 
 def find_trace_in_fig_data(data, search_string: str):
-    matches = filter(lambda x: x.name == search_string, data)
+    matches = (d for d in data if d.name == search_string)
     return next(matches)