diff --git a/aqt/cli.py b/aqt/cli.py
index eb88386..3c749be 100644
--- a/aqt/cli.py
+++ b/aqt/cli.py
@@ -94,13 +94,12 @@ class Cli():
 
     def _check_mirror(self, mirror):
         if mirror is None:
-            return
+            pass
         elif mirror.startswith('http://') or mirror.startswith('https://') or mirror.startswith('ftp://'):
             pass
         else:
-            self.parser.print_help()
-            exit(1)
-        return mirror
+            return False
+        return True
 
     def _check_modules_arg(self, qt_version, modules):
         if modules is None:
@@ -120,7 +119,9 @@ class Cli():
         modules = args.modules
         sevenzip = self._set_sevenzip(args)
         mirror = args.base
-        self._check_mirror(mirror)
+        if not self._check_mirror(mirror):
+            self.parser.print_help()
+            exit(1)
         if not self._check_qt_arg_combination(qt_version, os_name, target, arch):
             self.logger.warning("Specified target combination is not valid: {} {} {}".format(os_name, target, arch))
         if not self._check_modules_arg(qt_version, modules):
diff --git a/tests/test_cli.py b/tests/test_cli.py
index d0e16d9..dd154c9 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -2,8 +2,7 @@ import aqt
 
 
 def test_cli_help(capsys):
-    expected = "".join(["show help\n",
-                        "usage: aqt [-h] [--logging-conf LOGGING_CONF] [--logger LOGGER]\n",
+    expected = "".join(["usage: aqt [-h] [--logging-conf LOGGING_CONF] [--logger LOGGER]\n",
                         "           {install,tool,list,help} ...\n",
                         "\n",
                         "Installer for Qt SDK.\n",