函数：
aggregate_array(property)
Aggregates over a given property of the objects in a collection, calculating a list of all the values of the selected property.聚合集合中对象的给定属性，计算所选属性的所有值的列表。
Arguments:
this:collection (FeatureCollection):
The collection to aggregate over.
property (String):
The property to use from each element of the collection.
Returns: List
reduceColumns(reducer, selectors, weightSelectors)
Apply a reducer to each element of a collection, using the given selectors to determine the inputs.
Returns a dictionary of results, keyed with the output names.
将reduce应用于集合的每个元素，使用给定的选择器来确定输入。
返回结果字典，以输出名称为键
