diff --git a/examples/multi-language/python/wordcount_external.py b/examples/multi-language/python/wordcount_external.py
index eec64e0d0d10..7298d81c1b44 100644
--- a/examples/multi-language/python/wordcount_external.py
+++ b/examples/multi-language/python/wordcount_external.py
@@ -19,6 +19,7 @@
 
 import apache_beam as beam
 from apache_beam.options.pipeline_options import PipelineOptions
+from apache_beam.transforms.external import BeamJarExpansionService
 from apache_beam.transforms.external_transform_provider import ExternalTransformProvider
 from apache_beam.typehints.row_type import RowTypeConstraint
 """A Python multi-language pipeline that counts words using multiple Java SchemaTransforms.
@@ -67,17 +68,22 @@
 def run(input_path, output_path, expansion_service_port, pipeline_args):
     pipeline_options = PipelineOptions(pipeline_args)
 
-    provider = ExternalTransformProvider("localhost:" + expansion_service_port)
-    # Retrieve portable transforms
-    Extract = provider.get_urn(EXTRACT_IDENTIFIER)
-    Count = provider.get_urn(COUNT_IDENTIFIER)
-    Write = provider.get_urn(WRITE_IDENTIFIER)
-
     with beam.Pipeline(options=pipeline_options) as p:
+        expansion_service = BeamJarExpansionService(
+            "examples:multi-language:shadowJar")
+        if expansion_service_port:
+            expansion_service = "localhost:" + expansion_service_port
+
+        provider = ExternalTransformProvider(expansion_service)
+        # Retrieve portable transforms
+        Extract = provider.get_urn(EXTRACT_IDENTIFIER)
+        Count = provider.get_urn(COUNT_IDENTIFIER)
+        Write = provider.get_urn(WRITE_IDENTIFIER)
+
         _ = (p
              | 'Read' >> beam.io.ReadFromText(input_path)
              | 'Prepare Rows' >> beam.Map(lambda line: beam.Row(line=line))
-             | 'Extract Words' >> Extract(filter=["king", "palace"])
+             | 'Extract Words' >> Extract(drop=["king", "palace"])
              | 'Count Words' >> Count()
              | 'Format Text' >> beam.Map(lambda row: beam.Row(line="%s: %s" % (
                  row.word, row.count))).with_output_types(
@@ -100,8 +106,10 @@ def run(input_path, output_path, expansion_service_port, pipeline_args):
                         help='Output file')
     parser.add_argument('--expansion_service_port',
                         dest='expansion_service_port',
-                        required=True,
-                        help='Expansion service port')
+                        required=False,
+                        help='Expansion service port. If left empty, the '
+                        'existing multi-language examples service will '
+                        'be used by default.')
     known_args, pipeline_args = parser.parse_known_args()
 
     run(known_args.input, known_args.output, known_args.expansion_service_port,
diff --git a/examples/multi-language/src/main/java/org/apache/beam/examples/multilanguage/schematransforms/ExtractWordsProvider.java b/examples/multi-language/src/main/java/org/apache/beam/examples/multilanguage/schematransforms/ExtractWordsProvider.java
index 66bab336ce95..b7224ecec6b4 100644
--- a/examples/multi-language/src/main/java/org/apache/beam/examples/multilanguage/schematransforms/ExtractWordsProvider.java
+++ b/examples/multi-language/src/main/java/org/apache/beam/examples/multilanguage/schematransforms/ExtractWordsProvider.java
@@ -52,10 +52,10 @@ protected SchemaTransform from(Configuration configuration) {
 
   static class ExtractWordsTransform extends SchemaTransform {
     private static final Schema OUTPUT_SCHEMA = Schema.builder().addStringField("word").build();
-    private final List<String> filter;
+    private final List<String> drop;
 
     ExtractWordsTransform(Configuration configuration) {
-      this.filter = configuration.getFilter();
+      this.drop = configuration.getDrop();
     }
 
     @Override
@@ -73,7 +73,7 @@ public void process(@Element Row element, OutputReceiver<Row> receiver) {
                           String line = Preconditions.checkStateNotNull(element.getString("line"));
                           String[] words = line.split("[^\\p{L}]+", -1);
                           Arrays.stream(words)
-                              .filter(filter::contains)
+                              .filter(w -> !drop.contains(w))
                               .forEach(
                                   word ->
                                       receiver.output(
@@ -93,12 +93,12 @@ public static Builder builder() {
       return new AutoValue_ExtractWordsProvider_Configuration.Builder();
     }
 
-    @SchemaFieldDescription("List of words to filter out.")
-    public abstract List<String> getFilter();
+    @SchemaFieldDescription("List of words to drop.")
+    public abstract List<String> getDrop();
 
     @AutoValue.Builder
     public abstract static class Builder {
-      public abstract Builder setFilter(List<String> foo);
+      public abstract Builder setDrop(List<String> foo);
 
       public abstract Configuration build();
     }
diff --git a/sdks/python/apache_beam/transforms/external.py b/sdks/python/apache_beam/transforms/external.py
index e44f7482dc61..a4dd449e115a 100644
--- a/sdks/python/apache_beam/transforms/external.py
+++ b/sdks/python/apache_beam/transforms/external.py
@@ -239,7 +239,8 @@ def dict_to_row(schema_proto, py_value):
         extra = set(py_value.keys()) - set(row_type._fields)
         if extra:
           raise ValueError(
-              f"Unknown fields: {extra}. Valid fields: {row_type._fields}")
+              f"Transform '{self.identifier()}' was configured with unknown "
+              f"fields: {extra}. Valid fields: {set(row_type._fields)}")
         return row_type(
             *[
                 dict_to_row_recursive(