code: function WordCombination( words, occurrences, functionWords ) {
  	this._words = words;
  	this._length = words.length;
  	this._occurrences = occurrences || 0;
  	this._functionWords = functionWords;
  }
docs: Represents a word combination in the context of relevant words.
  
  @constructor
  
  @param {string[]} words The list of words that this combination consists of.
  @param {number} [occurrences] The number of occurrences, defaults to 0.
  @param {Function} functionWords The function containing the lists of function words.