diff --git a/cli/tests/integrations/test_marathon.py b/cli/tests/integrations/test_marathon.py
index 3225d0d..d469b2b 100644
--- a/cli/tests/integrations/test_marathon.py
+++ b/cli/tests/integrations/test_marathon.py
@@ -145,8 +145,8 @@ def test_missing_config(missing_env):
     assert_command(
         ['dcos', 'marathon', 'app', 'list'],
         returncode=1,
-        stderr=(b"Marathon likely misconfigured. Please check your proxy or "
-                b"Marathon URI settings. See dcos config --help. \n"),
+        stderr=(b'Missing required config parameter: "core.dcos_url".  '
+                b'Please run `dcos config set core.dcos_url <value>`.\n'),
         env=missing_env)
 
 
diff --git a/dcos/marathon.py b/dcos/marathon.py
index 37f0270..e3bda5c 100644
--- a/dcos/marathon.py
+++ b/dcos/marathon.py
@@ -37,11 +37,8 @@ def _get_marathon_uri(config):
 
     marathon_uri = config.get('marathon.url')
     if marathon_uri is None:
-        marathon_uri = config.get('core.dcos_url')
-        if marathon_uri is None:
-            raise DCOSException(_default_marathon_error())
-
-        marathon_uri = urllib.parse.urljoin(marathon_uri, 'marathon/')
+        dcos_url = util.get_config_vals(config, ['core.dcos_url'])[0]
+        marathon_uri = urllib.parse.urljoin(dcos_url, 'marathon/')
 
     return marathon_uri
 
@@ -49,7 +46,7 @@ def _get_marathon_uri(config):
 def _to_error(response):
     """
     :param response: HTTP response object or Error
-    :type response: requests.Response or Error
+    :type response: requests.Response | Error
     :returns: the error embedded in the response JSON
     :rtype: Error
     """
diff --git a/dcos/package.py b/dcos/package.py
index c9f838d..3f610f7 100644
--- a/dcos/package.py
+++ b/dcos/package.py
@@ -589,10 +589,7 @@ def list_sources(config):
     :rtype: [Source]
     """
 
-    source_uris = config.get('package.sources')
-
-    if source_uris is None:
-        raise DCOSException('No configured value for [package.sources]')
+    source_uris = util.get_config_vals(config, ['package.sources'])[0]
 
     sources = [url_to_source(s) for s in source_uris]
 
@@ -660,10 +657,7 @@ def update_sources(config, validate=False):
     errors = []
 
     # ensure the cache directory is properly configured
-    cache_dir = config.get('package.cache')
-
-    if cache_dir is None:
-        raise DCOSException('No configured value for [package.cache]')
+    cache_dir = util.get_config_vals(config, ['package.cache'])[0]
 
     # ensure the cache directory exists
     if not os.path.exists(cache_dir):
@@ -759,10 +753,7 @@ class Source:
         :rtype: str or None
         """
 
-        cache_dir = config.get('package.cache')
-        if cache_dir is None:
-            return None
-
+        cache_dir = util.get_config_vals(config, ['package.cache'])[0]
         return os.path.join(cache_dir, self.hash())
 
     def copy_to_cache(self, target_dir):