code: function(str, num) {
      str = String(str);
      // Reminder that this pretty much holds true only for English.
      return num === 1 || str.length === 0 ? str : inflectPlurals('plural', str);
    }
docs: *
  @method pluralize([num])
  @returns String
  @short Returns the plural form of the last word in the string.
  @extra If [num] is passed, the word will be singularized if equal to 1.
  Otherwise it will be pluralized. Custom pluralization rules can be
  added using `addPlural`.
  
  @example
  
  'post'.pluralize()    -> 'posts'
  'post'.pluralize(1)   -> 'post'
  'post'.pluralize(2)   -> 'posts'
  'octopus'.pluralize() -> 'octopi'
  'sheep'.pluralize()   -> 'sheep'
  
  @param {number} [num]
  
  *