final PropertyValue pv = checkKeywords(this.getValidKeywords(), value);
if (pv != null) {
collection.addItem(new PdFontStyle(pv));
collection.addItem(new PdFontVariant(pv));
collection.addItem(new PdFontWeight(pv));
collection.addItem(new PdFontSize(pv));
collection.addItem(new PdLineHeight(pv));
collection.addItem(new PdFontFamily(pv));
/*
* In addition to the properties explicitly set, font-stretch and
* font-size-adjust are set to their initial values by the "font"