code: @Override
  	public void setInputType(TypeInformation<?> type, ExecutionConfig executionConfig) {
  		if (!type.isTupleType()) {
  			throw new InvalidProgramException("The " + ScalaCsvOutputFormat.class.getSimpleName() +
  				" can only be used to write tuple data sets.");
  		}
  	}
docs: The purpose of this method is solely to check whether the data type to be processed
  is in fact a tuple type.