Be silent in case of lack of pylint

ftplugin/python/pylint_fn.py

@@ -9,7 +9,7 @@ try:
     from pylint import lint
     from pylint.reporters.text import TextReporter
 except ImportError:
-    raise AssertionError('Error: pylint_fm.vim requires module pylint')
+    pylint = None
 
 import vim
 
@@ -25,6 +25,10 @@ class VImPylint(object):
     def run(self):
         """execute pylint and fill the quickfix"""
 
+        if not pylint:
+            vim.command("echo 'Error: pylint_fm.vim requires module pylint'")
+            return
+
         # clear QF window
         vim.command('call setqflist([])')
 

ftplugin/python/pylint_fn.vim

@@ -46,7 +46,7 @@
 
 let s:plugin_path = expand('<sfile>:p:h', 1)
 
-if exists(":Pep8")
+if exists(":Pylint")
     finish " only load once
 endif