code: function(source, expression, value) {
      return this.getExpression(expression, { isSetter: true }).call(source, value);
    }
docs: Sets the value on the expression in the given context object
  @param {Object} context The context object the expression will be evaluated against
  @param {String} expression The expression to set a value with
  @param {mixed} value The value to set on the expression
  @return {mixed} The result of the expression against the context