code: function createErrorsManager() {
  
      return {
          illegalArgument: illegalArgument,
          propertyNotFound: propertyNotFound,
          propertyOverride: propertyOverride
      };
  
      function illegalArgument(arg, message) {
          var full = stringify(arg) + ': ' + message;
          throw new Error(formatMessage('Illegal argument', full));
      }
  
      function propertyNotFound(key, object) {
          if (config.throwPropertyNotFoundError) {
              var message = key + ' in ' + stringify(object);
              throw new Error(formatMessage('Property not found', message));
          }
      }
  
      function propertyOverride(key, object) {
          if (config.throwOverrideError) {
              var message = key + ' in ' + stringify(object);
              throw new Error(formatMessage('Property already exists',
                  message));
          }
      }
  
      function formatMessage(name, message) {
          if (!isString(message)) {
              message = stringify(message);
          }
          return config.filename + ': ' + name + ': ' + message;
      }
  }
docs: -------------------------------------- Errors --------------------------------------