How to use the @graphql-codegen/flow.FlowOperationVariablesToObject function in @graphql-codegen/flow

constructor(pluginConfig: FlowResolversPluginConfig, schema: GraphQLSchema) {
    super(pluginConfig, null, schema);
    autoBind(this);
    this.setVariablesTransformer(new FlowOperationVariablesToObject(this.scalars, this.convertName));
  }

convertName: this.convertName.bind(this),
      enumPrefix: this.config.enumPrefix,
      scalars: this.scalars,
      formatNamedField: (name: string): string => name,
      wrapTypeWithModifiers,
    };
    const processor = config.preResolveTypes
      ? new PreResolveTypesProcessor(processorConfig)
      : new FlowWithPickSelectionSetProcessor({
          ...processorConfig,
          useFlowExactObjects: this.config.useFlowExactObjects,
          useFlowReadOnlyTypes: this.config.useFlowReadOnlyTypes,
        });
    const enumsNames = Object.keys(schema.getTypeMap()).filter(typeName => isEnumType(schema.getType(typeName)));
    this.setSelectionSetHandler(new SelectionSetToObject(processor, this.scalars, this.schema, this.convertName.bind(this), allFragments, this.config));
    this.setVariablesTransformer(new FlowOperationVariablesToObject(this.scalars, this.convertName.bind(this), this.config.namespacedImportName, enumsNames, this.config.enumPrefix));
  }
}