code: public static final StyleSheet parseString(String css, URL base) throws IOException,
              CSSException {
  	    return parseString(css, base, getNetworkProcessor());
      }
docs: Parses text into a StyleSheet
  
  @param css
  Text with CSS declarations
  @param base
  The URL to be used as a base for loading external resources. Base URL may
  be {@code null} if there are no external resources in the CSS string
  referenced by relative URLs.
  @return Parsed StyleSheet
  @throws IOException
  When exception during read occurs
  @throws CSSException
  When exception during parse occurs