code: public static boolean isValidCSS (@Nonnull final File aFile,
                                      @Nonnull final Charset aCharset,
                                      @Nonnull final ECSSVersion eVersion)
    {
      return isValidCSS (new FileSystemResource (aFile), aCharset, eVersion);
    }
docs: Check if the passed CSS file can be parsed without error
  
  @param aFile
  The file to be parsed. May not be <code>null</code>.
  @param aCharset
  The charset to be used for reading the CSS file. May not be
  <code>null</code>.
  @param eVersion
  The CSS version to be used for scanning. May not be
  <code>null</code>.
  @return <code>true</code> if the file can be parsed without error,
  <code>false</code> if not