code: function and (left, right, options) {
    if (arguments.length < 3) {
      throw new Error('The "and" helper needs two arguments.');
    }
    return R.and(left, right) ?
      options.fn(this) : options.inverse(this);
  }
docs: Output a block (or its inverse) based on whether or not both of the supplied
  arguments are truthy.
  
  @since v0.0.1
  @param {*} left
  @param {*} right
  @param {Object} options
  @throws {Error} An error is thrown when the `right` argument is missing.
  @return {String}
  @example
  var a = true;
  var b = 1;
  var c = false;
  
  {{#and a b}}✔︎{{else}}✘{{/and}} //=> ✔︎
  {{#and b c}}✔︎{{else}}✘{{/and}} //=> ✘