希望新增一个接口

现有的是，可以查询某一段时间内的某个股票的流入情况，我希望能够有一个接口可以按照日期，获得当日所有股票的资金流入情况：

除此之外是否可以提供一个接口，不传入股票code，传入时间区间，直接返回整个市场这段时间的资金流动情况

Start by locating the existing interface that queries fund flows for one stock over a time range, then trace how its stock-code and date parameters are handled. Define the market-wide daily and date-range results requested here, and verify that both interfaces return the expected fund-flow data without a stock code.

Written by the indexing model from the issue text.