Missing Instruction/Error in Automation Script

Hi all,

I'm sure this is going to be some basic thing, but I am getting an error when my automation script runs, specifically this portion below. What is missing or not formatted correctly? It is intended to apply a conditional rule across column A that uses function RIGHT to find any number ending in 2 or 7 and apply custom formatting. 

Specific error in this case is:

Line 58: ConditionalFormatRule setFormula: The argument is invalid or missing or has an incorrect format.

Please let me know what other info is needed if any, thank you in advance!

	// Create custom from range A:A on selectedSheet
	conditionalFormatting = selectedSheet.getRange("A:A").addConditionalFormat(ExcelScript.ConditionalFormatType.custom);
	conditionalFormatting.getCustom().getRule().setFormula("=OR(RIGHT(A1,1)=\"\"2\"\",RIGHT(A1,1)=\"\"7\"\")");
	conditionalFormatting.getCustom().getFormat().getFill().setColor("#92d050");
	conditionalFormatting.getCustom().getFormat().getFont().setBold(true);
	conditionalFormatting.getCustom().getFormat().getFont().setItalic(false);
	conditionalFormatting.setStopIfTrue(false);
	conditionalFormatting.setPriority(0);
}