code: function(tank_id, nation, fields) {
  		return request({
  			hostname: hosts.wotb,
  			path: '/wotb/encyclopedia/vehicles/'
  		}, {
  			tank_id: tank_id ? tank_id.toString() : '',
  			nation: nation ? nation.toString() : '',
  			fields: fields ? fields.toString() : ''
  		});
  	}
docs: List of vehicle information
  
  @param {number|number[]} [tank_id] limit to this vehicle id(s) only
  @param {string|string[]} [nation] limit to vehicle in this tech tree(s)
  @param {string|string[]} [fields] response selection
  @returns {Promise<Object>} resolves to description of requested vehicles