Use vim-lsp instead of ale

python.vim

@@ -3,3 +3,12 @@ au BufNewFile,BufRead *.py
     \ setlocal foldmethod=indent 
     \ nospell
 
+" register pyls as a language server.
+if executable('pyls')
+    " pip install python-language-server
+    au User lsp_setup call lsp#register_server({
+        \ 'name': 'pyls',
+        \ 'cmd': {server_info->['pyls']},
+        \ 'allowlist': ['python'],
+        \ })
+endif