How to use the @amalto/helpers.downloadDataFile function in @amalto/helpers

private downloadFile = ( event: any ) => {
        const key: string = event.currentTarget.getAttribute( 'data-key' )
        downloadDataFile( this.props.keyValues[key].contentBytes, this.props.keyValues[key].contentType, key )
    }

private downloadFile = ( key: string ) => {
        downloadDataFile( this.props.keyValues[key].contentBytes, this.props.keyValues[key].contentType, key )
    }

private downloadFile = ( event: any ) => {
        if ( this.state.selectedNode ) {
            const keyValues: KeyValDef = this.state.selectedNode.data.propertiesMap
            const key: string = event.currentTarget.getAttribute( 'data-key' )
            downloadDataFile( keyValues[key].contentBytes, keyValues[key].contentType, key )
        }
    }