Improve code quality, fix potential bugs

pypgn/game.py

@@ -105,7 +105,7 @@ def event(self) -> str:
 
         :return: Event name
         """
-        return self.tag('Event' if 'Event' in self.tags else '')
+        return self.tag('Event' if self.tags is not None and 'Event' in self.tags else '')
 
     def result(self) -> str:
         """Gets and returns the game result
@@ -120,7 +120,7 @@ def date(self) -> str:
 
         :return: Date of the game in format YYYY.MM.DD
         """
-        return self.tag('Date' if 'Date' in self.tags else 'UTCDate')
+        return self.tag('Date' if self.tags is not None and 'Date' in self.tags else 'UTCDate')
 
     def move_range(self, start: int = 1, end: int = None) -> List[Move]:
         """Gets and returns a range of moves

pypgn/game_utils.py

@@ -1,7 +1,6 @@
 import re
-import http.client
 from typing import List, NewType, Union
-from http.client import HTTPException
+from http.client import HTTPException, HTTPSConnection
 
 Move = NewType('Move', Union[str, List])
 
@@ -48,7 +47,7 @@ def _get_moves(pgn: list) -> List[Move]:
 
 
 def _get_lichess_pgn_lines(src: str) -> list:
-    conn = http.client.HTTPSConnection("lichess.org")
+    conn = HTTPSConnection("lichess.org")
 
     payload = ""
     endpoint = "/game/export/"