code: function relativeFrequencies(sequence) {
    let index,
        length;
  
    // Handling the object polymorphism
    if (typeof sequence === 'object' && !Array.isArray(sequence)) {
      index = sequence;
      length = 0;
  
      for (const k in index)
        length += index[k];
    }
    else {
      length = sequence.length;
      index = frequencies(sequence);
    }
  
    const relativeIndex = {};
  
    for (const k in index)
      relativeIndex[k] = index[k] / length;
  
    return relativeIndex;
  }
docs: Relative version of the `frequencies` function.
  
  @param  {mixed}  sequence - The sequence to process. If an object is passed
  the function will assume it's representing
  absolute frequencies.
  @return {object}          - A dict of the sequence's relative frequencies.
  
  @example
  // frequencies([1, 1, 2, 3, 3, 3]) => {1: ~0.33, 2: ~0.16, 3: 0.5}
  // frequencies('test') => {t: 0.5, e: 0.25, s: 0.25}