code: public static String escapePropertiesKey(final String text, final PropertiesKeyEscapeLevel level) {
  
          if (level == null) {
              throw new IllegalArgumentException("The 'level' argument cannot be null");
          }
  
          return PropertiesKeyEscapeUtil.escape(text, level);
      }
docs: <p>
  Perform a (configurable) Java Properties Key <strong>escape</strong> operation on a <tt>String</tt> input.
  </p>
  <p>
  This method will perform an escape operation according to the specified
  {@link org.unbescape.properties.PropertiesKeyEscapeLevel} argument value.
  </p>
  <p>
  All other <tt>String</tt>-based <tt>escapePropertiesKey*(...)</tt> methods call this one with
  preconfigured <tt>level</tt> values.
  </p>
  <p>
  This method is <strong>thread-safe</strong>.
  </p>
  
  @param text the <tt>String</tt> to be escaped.
  @param level the escape level to be applied, see {@link org.unbescape.properties.PropertiesKeyEscapeLevel}.
  @return The escaped result <tt>String</tt>. As a memory-performance improvement, will return the exact
  same object as the <tt>text</tt> input argument if no escaping modifications were required (and
  no additional <tt>String</tt> objects will be created during processing). Will
  return <tt>null</tt> if input is <tt>null</tt>.