code: private void generateOpen(String schemaName) {
  		MethodSpec.Builder methodBuilder = MethodSpec.methodBuilder("open")
  				.addModifiers(Modifier.PUBLIC, Modifier.STATIC).returns(className(schemaName));
  
  		methodBuilder.addJavadoc("Retrieve data source instance and open it.\n");
  		methodBuilder.addJavadoc("@return opened dataSource instance.\n");
  
  		methodBuilder.addStatement("$L instance=getInstance()", schemaName);
  
  		methodBuilder.addStatement("instance.openWritableDatabase()");
  		methodBuilder.addCode("return instance;\n");
  
  		classBuilder.addMethod(methodBuilder.build());
  	}
docs: Generate open.
  
  @param schemaName
  the schema name