function set( labels ) {
	/* eslint-disable no-invalid-this */
	if ( !isEmptyArray( labels ) && !isStringArray( labels ) ) {
		throw new TypeError( format( 'invalid assignment. `%s` must be an array of strings or an empty array. Value: `%s`.', 'labels', labels ) );
	}
	debug( 'Current value: %s.', JSON.stringify( this._labels ) );

	this._labels = labels.slice();
	debug( 'New Value: %s.', JSON.stringify( this._labels ) );

	this.emit( 'change' );
}
Sets the data labels.

@private
@param {(StringArray|EmptyArray)} labels - data labels
@throws {TypeError} must be either an array of strings or an empty array