docs: function () {
    return {
      inheritPrototype: inheritPrototype,
      getInvalidProperties: getInvalidProperties,
      trim: trim,
      ltrim: ltrim,
      rtrim: rtrim,
      left: left,
      center: center,
      right: right,
      lpad: lpad,
      rpad: rpad,
      cpad: cpad,
      contains: contains,
      injectMethods: function (that) {
        that.inheritPrototype = inheritPrototype;
        that.getInvalidProperties = getInvalidProperties;
        that.trim = trim;
        that.ltrim = ltrim;
        that.rtrim = rtrim;
        that.left = left;
        that.center = center;
        that.right = right;
        that.lpad = lpad;
        that.rpad = rpad;
        that.cpad = cpad;
        that.contains = contains;
      }
    };
  }