Address comments.

src/Microsoft.ML.Core/Utilities/PathUtils.cs

@@ -159,7 +159,7 @@ public static string MakePathRelative(string basepath, string path)
 
             if (baseUri.Scheme != uri.Scheme)
             {
-                throw new ArgumentException("Paths cannot be made relative as they are of different schemas.");
+                throw new ArgumentException("Paths cannot be made relative as they are of different schemes.");
             }
 
             string relativePath;
@@ -196,8 +196,10 @@ public static string MakePathRelative(string basepath, string path)
         /// <returns>An enumerable list of all non-empty directories.</returns>
         public static IEnumerable<string> SplitDirectories(string path)
         {
+            char [] separators = { Path.DirectorySeparatorChar };
+
             var cleanPath = path.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
-            return cleanPath.Split(new char[] { Path.DirectorySeparatorChar }, StringSplitOptions.RemoveEmptyEntries);
+            return cleanPath.Split(separators, StringSplitOptions.RemoveEmptyEntries);
         }
     }
 }

src/Microsoft.ML.Data/DataLoadSave/PartitionedFileLoader.cs

@@ -175,7 +175,7 @@ public PartitionedFileLoader(IHostEnvironment env, Arguments args, IMultiStreamS
             _host.CheckValue(files, nameof(files));
 
             _pathParser = args.PathParserFactory.CreateComponent(_host);
-            _host.CheckValue(_pathParser, nameof(_pathParser), "Factory failed to create a FilePathSpec");
+            _host.CheckValue(_pathParser, nameof(_pathParser), "Failed to create the FilePathSpec.");
 
             _subLoader = args.Loader;
             _files = files;