- server.py: compatibility with pypy3 (e.g. python 3.6) fixed

DHParser/server.py

@@ -41,6 +41,7 @@ For JSON see:
     https://json.org/
 """
 
+# TODO: Test with python 3.5
 
 import asyncio
 from concurrent.futures import ThreadPoolExecutor, ProcessPoolExecutor, CancelledError
@@ -54,6 +55,7 @@ from DHParser.syntaxtree import DHParser_JSONEncoder
 from DHParser.toolkit import get_config_value, re
 from DHParser.versionnumber import __version__
 
+
 __all__ = ('RPC_Table',
            'RPC_Type',
            'JSON_Type',
@@ -400,7 +402,7 @@ class Server:
                 self.loop.run_forever()
             finally:
                 self.server.close()
-                self.server.wait_closed()
+                asyncio_run(self.server.wait_closed())
 
     def _empty_message_queue(self):
         while not self.server_messages.empty():