update ReadME

tools/python/copy-table/README.md

@@ -85,15 +85,15 @@ Target bucket and error bucket names are given by *s3_target_bucket* and *s3_tar
 Destination prefix will be created with prefix dest/ given by *destination_s3_prefix*. Desired data model file is chosen as *data_model_sample.json* in the current location of the script. 
 
  ```bash
-python batch_load.py --region us-west-2 --create_timestream_resource --database=targetdb --table=myTable --partition_key city --copy_s3_bucket --s3_source_bucket_location  timestream-unload-sourcedb-mytable --source_s3_prefix unload/results/ --create_destination_bucket --s3_target_bucket timestream-batchload-targetdb-mytable --destination_s3_prefix dest/ --create_error_logging_bucket --s3_target_error_bucket timestream-batchload-error-logs --data_model_file "data_model_sample.json"      
+python3 batch_load.py --region us-west-2 --create_timestream_resource --database=targetdb --table=myTable --partition_key city --copy_s3_bucket --s3_source_bucket_location  timestream-unload-sourcedb-mytable --source_s3_prefix unload/results/ --create_destination_bucket --s3_target_bucket timestream-batchload-targetdb-mytable --destination_s3_prefix dest/ --create_error_logging_bucket --s3_target_error_bucket timestream-batchload-error-logs --data_model_file "data_model_sample.json"      
 ```
 
 **Without S3 Copy** 
 Example to execute a batch load to the target Timestream table *myTable* with partition key *city* in the database *targetdb* with  *eu-west-1* region.
 Timestream objects are created by this script as per *create_timestream_resource* parameter. Source data are located in the S3 bucket *timestream-unload-sourcedb-mytable* with prefix *unload/results/*.
 Error logs are stored into S3 bucket *timestream-batchload-error-logs*. If you need error log buckets to be created specify --create_error_logging_bucket.
  ```bash
-python batch_load.py --region eu-west-1 --database=targetdb --table=myTable  --s3_target_bucket timestream-unload-sourcedb-mytable --destination_s3_prefix unload/results/  --data_model_file "data_model_sample.json" --create_timestream_resource --partition_key city   --s3_target_error_bucket timestream-batchload-error-logs
+python3 batch_load.py --region eu-west-1 --database=targetdb --table=myTable  --s3_target_bucket timestream-unload-sourcedb-mytable --destination_s3_prefix unload/results/  --data_model_file "data_model_sample.json" --create_timestream_resource --partition_key city   --s3_target_error_bucket timestream-batchload-error-logs
 ```
 
 ## Usage and Requirements