ERROR : java.lang.IllegalArgumentException: Missing required pipeline options: region

I have Data in BigQuery and trying to migrate that to BigTable using `BigQueryBigtableTransfer` DF template.
running it like
```
mvn package exec:exec \
-DBigQueryBigtableTransfer \
-Dbigtable.projectID=google-cloud-project-id \
-Dbigtable.instanceID=Big-table-instance-id-dev \
-Dgs=gs://google-cloud-project-id-bigtable/bigtable_table/ \
-Dbq.query='SELECT * FROM `google-cloud-project-id.SAMPLE.bigtable_test`' \
-Dregion=us-west1
```
With or without region still gives error of region parameter missing even if region paramater is no where mentioned in redme file.
getting below error -
```
[INFO] --- exec-maven-plugin:1.4.0:exec (default-cli) @ dataflow-connector-examples ---
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/C:/Users/xyz/.m2/repository/org/slf4j/slf4j-log4j12/1.7.25/slf4j-log4j12-1.7.25.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/C:/Users/xyz/.m2/repository/org/slf4j/slf4j-simple/1.7.21/slf4j-simple-1.7.21.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
log4j:WARN No appenders could be found for logger (org.apache.beam.sdk.options.PipelineOptionsFactory).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Exception in thread "main" java.lang.RuntimeException: Failed to construct instance from factory method DataflowRunner#fromOptions(interface org.apache.beam.sdk.options.PipelineOptions)
at org.apache.beam.sdk.util.InstanceBuilder.buildFromMethod(InstanceBuilder.java:224)
at org.apache.beam.sdk.util.InstanceBuilder.build(InstanceBuilder.java:155)
at org.apache.beam.sdk.PipelineRunner.fromOptions(PipelineRunner.java:55)
at org.apache.beam.sdk.Pipeline.create(Pipeline.java:149)
at com.google.cloud.bigtable.dataflow.example.BigQueryBigtableTransfer.main(BigQueryBigtableTransfer.java:118)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.beam.sdk.util.InstanceBuilder.buildFromMethod(InstanceBuilder.java:214)
... 4 more
Caused by: java.lang.IllegalArgumentException: Missing required pipeline options: region
at org.apache.beam.runners.dataflow.DataflowRunner.fromOptions(DataflowRunner.java:262)
... 9 more
```

Can you please advice whats wrong?