zaki@C800D:~/Downloads/gns3-server$ gns3server
Traceback (most recent call last):
  File "/usr/local/bin/gns3server", line 11, in <module>
    load_entry_point('gns3-server===2.1.1dev1-840aa394', 'console_scripts', 'gns3server')()
  File "/usr/local/lib/python3.6/dist-packages/gns3_server-2.1.1dev1_840aa394-py3.6.egg/gns3server/main.py", line 82, in main
    from gns3server.run import run
  File "/usr/local/lib/python3.6/dist-packages/gns3_server-2.1.1dev1_840aa394-py3.6.egg/gns3server/run.py", line 32, in <module>
    from gns3server.web.web_server import WebServer
  File "/usr/local/lib/python3.6/dist-packages/gns3_server-2.1.1dev1_840aa394-py3.6.egg/gns3server/web/web_server.py", line 46, in <module>
    raise RuntimeError("aiohttp 2.2 is required to run the GNS3 server")
RuntimeError: aiohttp 2.2 is required to run the GNS3 server