function set( padding ) {
	/* eslint-disable no-invalid-this */
	var err = isValid( padding );
	if ( err ) {
		throw err;
	}
	debug( 'Current value: %d.', padding );

	this._tickPadding = padding;
	debug( 'New Value: %s.', this._tickPadding );

	this.emit( CHANGE_EVENT );
}
Sets the axis tick padding.

@private
@param {NonNegativeInteger} padding - padding
@throws {TypeError} must be a nonnegative integer