void (PyExpression arg, ASTNode beforeThis, boolean commaFirst) { ASTNode comma = PyElementGenerator.getInstance(getProject()).createComma(); ASTNode node = getNode(); ASTNode argNode = arg.getNode(); if (commaFirst) { node.addChild(comma, beforeThis); node.addChild(ASTFactory.whitespace(" "), beforeThis); node.addChild(argNode, beforeThis); } else { node.addChild(argNode, beforeThis); node.addChild(comma, beforeThis); node.addChild(ASTFactory.whitespace(" "), beforeThis); } }