code: function allowOverride (allowOverride) {
      // set default if value passed
      if (defined(allowOverride)) {
          immutable.defaultAllowOverride = allowOverride ? true : false
          // return immutable
          return ImmutableCore
      }
      // return default value
      return immutable.defaultAllowOverride
  }
docs: @function allowOverride
  
  get/set the default value for allowing override of methods and cache rules
  
  @param {boolean} strictArgs
  
  @returns {ImmutableCore|boolean}