code: function preset (key, format) {
    validator('format', format)
  
    if (presets[key] !== undefined) {
      throw new SyntaxError('It is not allowed to override existing presets.')
    }
  
    presets[key] = format
  }
docs: @function
  @public
  
  Add a format preset to collection.
  
  @param {string} key The name of the preset
  @param {string | boolean} format The format string to be preset
  
  @throws The passed key already exists